Prime Time

Cover Photo: Summer is the peak season for raising your own produce, including golden beets and watermelon radishes, and sharing it with others.
photograph by ROB CARDILLO

IN THIS ISSUE

by SCOTT MEYER
photographs by ROB CARDILLO

Garden-tested strategies for your most bountiful season ever.

Experienced gardeners can’t tell you the one secret to success with a vegetable garden, but most of them know a few tips that can help you harvest bumper crops of your favorite homegrown foods. We’ve gathered this batch of hints and tricks from gardeners in our region to help you get more from your plot this year.

With that bigger yield, you can participate in City Harvest, the PHS effort to increase access to fresh food for all. If you make a commitment to sharing some of your crops with your community, typically through a local food pantry, you are eligible for free seedlings (see KNOW in this issue), bulk compost and mulch, other supplies, and access to the PHS McLean Urban Agriculture Tool Library at Glenwood Green Acres.

Prep soil. “I don’t till my beds in spring, but I get a pitchfork in there to loosen and aerate the soil before seedlings and seeds are planted,” says Christie Sommers, a gardener in Wyndmoor, Pennsylvania. “At the end of the season, I cut the stems of spent plants, like tomatoes, at the base and leave the root systems intact to break down over winter and feed the soil” for the following season.  

Rotate crops. Even if you don’t have a lot of space in your garden, try to avoid planting the same crops in the same spots every season. “Rotating crops helps reduce soilborne diseases and pests that can build up in the soil over time,” advises Nancy Trautz-Awot, a horticulture specialist at Burpee Seed Company’s Fordhook Farm in Doylestown, Pennsylvania.

Rise up. Squash vine borers suck the sap from the vines of cucurbit crops, such as zucchini and cucumbers. To keep the pests away, grow these crops up a trellis or cage, recommends Scott Meyer,  the editorial director of GROW. Training these vines this way keeps them off the soil, where pests can get into them. It also saves space in your garden and makes the fruit easy to see and harvest.

Plant deeply. Tomatoes have a unique ability to develop roots along their stems when they are underground. Planting tomatoes deeper than they were in their pots “encourages the formation of additional roots that increase the plants’ stability as they grow,” Trautz-Awot says. “These extra roots mean more access to water and nutrients, which results in healthier plants with bigger yields.” 

Block weeds. “A great way to keep undesirable plants from invading veggie beds is to give them nowhere to go,” Sommers says. “If you include companion plants of varying heights, the plants close to the ground fill in and act as groundcover. For example, try asparagus in a bed with strawberries at its feet, or intersperse root veggies, like beets and carrots, with tomato plants. The tomato plants shade the beets from the hot summer sun while the beet greens leave little room for undesirable plants to pop up.”

Throw shade. When the days grow longer in summer, many cooler-season crops, such as kale, lettuce, and other salad greens, bolt (flower and begin producing seeds) in the bright sunshine. You can extend their growing season by “creating partial shade with taller plants around them,” says Emma Ford, propagation manager for the PHS City Harvest program. “You can also set up row covers to shade the cooler-season crops through the summer.”

Sow often. Extend the harvest time for short-maturity crops, such as radishes and carrots, with succession planting. “Plant them in small batches weekly to harvest perfectly mature vegetables all season long,” says Patrick McDonough Jr., senior product manager at Burpee. If you forget about the timing, just sow the next round of seeds when the seedlings from the previous batch reach 3 inches tall.

Pick perennials. Plant once and harvest for years to come. That’s what you get from perennial food crops, such as asparagus, rhubarb, lovage, raspberries, and grapes. “Once established, they require minimal care aside from yearly harvesting and pruning,” Sommers says. “And in my experience, they require less watering during dry spells than more commonly grown veggies like tomatoes and cucumbers. Bonus points if they pull double duty in the garden. For instance, grapevines grown over a trellis make excellent shade covering, and I use the pruned vines for basketry, weaving cloche covers for sensitive plants, and creating wattle fencing in the garden.”

Resist rot. Blossom-end rot is a common problem in tomatoes, as well as peppers, eggplant, and summer squash. It shows up when the tissue on the opposite side from the stem develops dark, soft, watery spots. Blossom-end rot is caused by calcium deficiency in the soil. To prevent it, Ford of PHS City Harvest treats those crops with a homemade formula using eggshells that are lightly roasted in the oven to burn off any remaining organic matter. (Oyster or clam shells would work too.) The shells are broken up and soaked for a week to 10 days in vinegar to dissolve the calcium. The liquid is then strained into a spray bottle and misted onto the plants during their reproductive stage. Get all the details from the University of Hawai‘i at Mānoa.

Groom tomatoes. Soilborne diseases, such as verticillium and fusarium wilts, can splash onto the lower leaves of tomato plants, and the infection spreads upward. “Removing these leaves reduces the risk of infections,” Trautz-Awot says. “At the Burpee test garden, we always remove the bottom leaves.” Use a pair of sharp pruners to snip off all the branches on the lowest 5 to 6 inches of the stems.

Supply salt. Magnesium and sulfur are essential minerals for plants, and they support chlorophyll production and other key processes. When the soil is deficient in these minerals, foliage may look yellow or stunted. To ensure a sufficient supply, Nia Dixon, a community gardener in North Philadelphia and a frequent PHS volunteer (see KNOW in this issue) supplements the soil in her raised beds with Epsom salt, or magnesium sulfate, a chemical compound made up of magnesium, sulfur, and oxygen. The Epsom Salt Council recommends sprinkling 1 cup of the compound onto every 100 square feet of soil and mixing it in before planting. 

Make mulch. You can find useful mulch materials around your house. For instance, “save cardboard boxes from shipping packages, cut them to lie flat, and place them around the plants in your garden to suppress weeds,” McDonough says. “Cover the cardboard with a thin layer of mulch or soil to hold it in place. The cardboard gradually becomes porous and fully breaks down in as little as six months.”

Beat weeds. “Most of the weeds that appear in my garden have medicinal uses,” Sommers says. “I pull and dry purple deadnettle (Lamium purpureum, above) to use for a tea blend that has worked well for my family at reducing the effects of seasonal allergies. Hairy bittercress (Cardamine hirsuta) is everywhere, but if you pull it before it starts launching seeds (often into your eyes), it’s a nice peppery green that makes a healthy addition to salads.” In other words, if you can’t beat them, eat them.

Water wisely. You can keep your crops fully hydrated while using a valuable resource efficiently. Direct water to the soil, where plants’ roots can absorb it, rather than to the leaves, which don’t take it in. Also, “water your plants deeply and infrequently, allowing the soil to dry out slightly” before you sprinkle them again, Trautz-Awot says. “Use mulch to retain moisture and suppress weeds,” which siphon away water and nutrients from your crops.

Three More Ways to Learn

You can certainly pick up tips from talking to fellow gardeners, but as a PHS member, you have access to a wide variety of other resources for broadening your knowledge and skills.

Workshops. This season’s calendar is packed with demonstrations and classes for gardeners of all levels of experience. For 2024, PHS is partnering with the experts at Chanticleer, the public garden in Wayne, Pennsylvania, on a special workshop series. PHS members receive a discount on registration fees. Check the calendar for topics and times.

PHS McLean Library. With more than 15,000 books and videos, 70 subject-specific guides, and a vast collection of e-books, the library offers you in-depth information on just about any gardening topic that interests you. Visit the library online to learn more.

Volunteering. Give a little of your time helping out at the PHS Green Resource Centers or public landscapes and you’re sure to learn from the pros who guide the volunteers. You also get to meet other gardeners and share your knowledge with each other. See the details and schedule here.

BACK TO TOP

PHS volunteers help plant hundreds of bulbs for a spring display at Logan Circle.

PHS volunteers help plant hundreds of bulbs for a spring display at Logan Circle.

HOT LOOKS

Tropical plants light up your landscape and containers with brilliant hues and extraordinary textures.

Above: The mammoth leaves of Leucocasia gigantea (also known as Colocasia gigantea) ‘Thailand Giant’ attract your eyes, while various bromeliads attached to metal columns simulate jungle tree trunks. “You could achieve the same effect by sinking fallen branches into a bed or container,” Benarcik says.

YOU MAY LIVE IN THE TEMPERATE ZONE OF THE MID-ATLANTIC REGION, but you can enjoy the look and feel of the tropics in your garden. Warm-climate species bring rich colors and lush foliage to your flowerbeds and ornamental pots, and they thrive in our hot, humid summer weather. “I love how plants that are not from here add diversity to our gardens,” says Dan Benarcik, senior horticulturist at Chanticleer, the public garden in Wayne, Pennsylvania, where the photographs in this gallery were shot. “Because tropical plants are not hardy here, we have to lift them out and replant them the next season. I like that they force our gardens to change from year to year.”

These images offer you a variety of ideas for incorporating tropical plants into your space. You’ll find more inspiration and suggestions for how to use them when you check out the beds and planters at PHS public landscapes, including Logan Square and Swann Memorial Fountain, LOVE Park, and the PHS Pop Up Gardens at South Street and Manayunk. All of them include tropicals that add vibrancy and variety to their displays. (See DISCOVER for details and locations.)

 Click on any of the photos to open the full gallery and find out more about the tropical plants shown.

Lasting Effects

SEE HOW A LANDSCAPE ARCHITECT HAS DESIGNED A CONTEMPORARY GARDEN FULL OF NATIVE PLANTS TO ENHANCE A TRADITIONAL HOME.

CHADDS FORD, IN PENNSYLVANIA’S BRANDYWINE RIVER VALLEY, is renowned for its rolling hills, historic farmsteads, and the talented Wyeth family of artists. Many area homeowners love the ubiquitous “old farm” vernacular so much that they update the interiors of the houses and other structures while preserving the weathered exteriors to better blend into the surroundings. Jonathan Alderson, a landscape architect in Wayne, Pennsylvania, helped one local family to create gardens that would fit into the bucolic landscape outside their home.

To complement the existing hardscape, Alderson used rough agricultural and industrial materials matched with a mostly native plant palette. We asked him to explain the other design and plant choices around the property. Click on the different areas of these photos to see the details.

 Scroll down to learn all the details about this landscape.

Viewed from the drive, the house fits in comfortably with the terrain while the planted hillside keeps the swimming pool out of sight from passersby.

After the rosy pink to purple blooms of this red bud tree (Cercis canadensis) fade in late spring, its attractive dark purple foliage stands out among the lighter greens surrounding it.

Along the driveway, an extensive meadow blooms with mountain mint, helianthus, bee balm rudbeckia, goldenrod, and other wildflowers. They were established with plugs (seedlings with large root systems) planted in groups of 10 to 20.

Native junipers are tall, upright evergreens with needles that turn a shade of bronze purple in winter, but they carry cedar-apple rust disease, which can disfigure nearby crabapples. For this landscape, Alderson chose cryptomeria trees, which are similar in color and shape but not vectors for the disease.

The small native magnolia opens its large and fragrant white flowers in May and June.

A long patio shaded by a mix of trees and shrubs provides an ideal place for a custom-made table to host large gatherings.

A native wisteria has been trained on a corn-crib trellis and now screens the view from the driveway. Abelias lend a delicate structure that softens the patio’s edge.

Four Chinese fringe trees planted in a square form the pillars and roof of a garden room.

The existing barn wall and picket fencing enclose a “secret garden.” Hydrangeas and roses growing along the fence add color and privacy.

Inside the wall, a turfgrass lawn is planted with flowering alliums, which require a no-mow period after blooming to regenerate their bulbs.

A grassy ramp leads to the main living area of the three-level house. Inside the old silo is a spiral staircase, and outside, a stand of calamagrostis grass creates a visual link to the surrounding landscape. Inlays of grass in the cobblestone driveway replicate the look of a country lane.

A warm-season grass meadow dotted with echinacea and bee balm transitions into the uncultivated areas on the property.

A native river birch shades the crushed-gravel parking area.

Higher Ground

Raised beds elevate your vegetable garden’s yields and enhance its appearance while saving you labor.

UNLESS YOU’RE GROWING ACRES OF CROPS, raised beds provide the best strategy for creating a garden that is productive and easy to maintain. They are simply planting areas of soil mounded 6 inches or higher above the ground level. Raised beds can be temporary, but gardeners typically leave them in place from one season to the next. Permanent beds can be framed with a wide range of materials, which can transform a vegetable patch into a beautiful garden.

BENEFITS PACKAGE

Soil solution. With raised beds, you can overcome nearly any soil challenge. Heavy clay stays soggy long after a storm. In raised beds, rainfall percolates through the soil, hydrating your plants before draining away. Sandy soil lets moisture go too fast and doesn’t retain nutrients. The organic matter in raised beds acts like a sponge, releasing water as needed, and provides key minerals to your crops. Raised beds are also effective for urban gardeners who want to avoid digging down in soil that may contain utility lines, large debris, or even contaminants.

Room for roots. In raised beds, the soil stays loose and fluffy because you never walk on it. That allows plants’ roots to grow and spread easily and to find and absorb water and nutrients. Robust root systems support robust crops, which bear robust harvests.   

Higher yields. You can set plants more closely in a raised bed than in a ground-level plot because the deep, loose soil allows roots to go down rather than spread out. Experienced gardeners typically set their seeds or seedlings in a triangular or staggered pattern so that the leaves overlap slightly at maturity. You get in more plants per square foot, and the continuous leafy canopy shades the bed, moderates soil temperatures, conserves moisture, and discourages weeds. Note that the tactic of close spacing requires careful planning to account for each crop’s growing habits, including root spread, mature size, and water and nutrient needs.

Earlier start. Raised beds warm up faster and dry out sooner than flat ground, so you can plant your spring crops earlier in the season.

Plant protection. When you clearly define the growing space in your garden, everyone will see where to walk without stepping on your plants. 

Increased access. For gardeners in wheelchairs or others who are not able to kneel or bend easily, high raised beds can put the garden right where they can reach it. The ideal height for an accessible plot is 28 to 34 inches above the ground.

Good looks. As you can see in the photos accompanying this story, raised beds can bring order to a garden and provide the structure that transforms rows of vegetables into an attractive landscape.

BUILDING UP

Double digging is the traditional method of making raised beds. This process involves removing 6 inches of topsoil from the bed, loosening 6 inches of subsoil, and then replacing the topsoil with lots of organic matter mixed in. Double digging creates hospitable conditions for your crops, but it is time-consuming, laborious, and unnecessary.

A quicker and easier approach is to work a lot of organic matter, such as compost, shredded leaves, or well-rotted manure, into the top 6 inches. This adds the volume that elevates the bed and creates the environment where plants’ roots thrive. You won’t need to repeat the whole process each year, but adding a few inches of organic matter every spring keeps the bed topped off.

Where digging into the topsoil is not possible or desirable, you can build raised beds from the ground up with bulk or bagged soil and compost. Just mix those materials together in roughly equal amounts and mound them up to the desired height.

If you intend the beds to be temporary or you don’t plan to frame them, use a rake to mound up and shape the soil so that it is flat on the surface and has sloping sides. (This shape helps conserve water.) The ideal width for raised beds is about 4 feet, so you can reach in to tend the plants from either side. You can make the bed any length you want, but 8 to 10 feet is a common size for home gardens. The soil in unframed beds gradually spreads out and needs to be periodically hilled up with a rake or hoe.

Once you establish your raised beds, don’t tread on the soil, which can compress the air pockets that roots need.

Fill raised beds with lots of organic matter, such as compost.

Fill raised beds with lots of organic matter, such as compost.

Raised bed frames can be simply functional or add structure and style to your vegetable garden.

Raised bed frames can be simply functional or add structure and style to your vegetable garden.

Repurposed wood can be an inexpensive option.

Repurposed wood can be an inexpensive option.

Think outside the rectangle and use your raised beds as part of your landscape design.

Think outside the rectangle and use your raised beds as part of your landscape design.

You can set plants close together in raised beds.

You can set plants close together in raised beds.

FINISHING TOUCHES

Framing your raised beds helps slow soil erosion and clearly defines them for you and others who walk through the space. You also get a chance to bring a little of your own style to your garden through the materials you select for framing.  

You can go with a simple and inexpensive option, such as large stones, cinder blocks, or salvaged bricks, that you set around the perimeter of the beds. Fallen timber can even serve as a rough frame.

Frames made with sections of lumber nailed or screwed together create a more polished look. You can use almost any kind of wood, but cedar, cypress, and locust are naturally rot-resistant. They tend to be pricey, but they last for years. If you go with a lower-priced type of lumber, be sure to pass on “pressure-treated” wood or used railroad ties, which may contain toxins that leach into the soil. Planks made with recycled plastic aren’t as attractive, but they can last for years too.

Corrugated steel has become a popular framing material because of its sleek look and durability. Livestock watering tanks are ready-made raised beds at just the right height for seated gardeners.

Many local and online gardening suppliers offer raised bed kits you can set up in minutes. They are typically made of wood, metal, or plastic. Most are in standard rectangles, but you can find square and more rounded shapes to fit your taste and space. Kits for tall beds that are designed to be accessible to all are also widely available.

Want to harvest even more from your raised beds? To your frames, attach metal hoops that can be covered with plastic or agricultural fabric (such as the Reemay brand) to create a low tunnel in which plants can survive colder temperatures than they could withstand if they were fully exposed. Many raised bed kits now come with fittings for low tunnels included.

When your raised beds are finished, cover the soil with a layer of natural mulch such as dried grass clippings or pine straw. The mulch prevents weeds from sprouting and keeps the soil cool until your crops grow big enough to shade the ground.    

BACK TO TOP

PHS Public Gardens & Landscapes

PHILADELPHIA

Above: The Azalea Garden behind the Philadelphia Museum of Art includes space for kids to frolic while adults enjoy the colorful floral display. 

WHY VISIT?

Spending time in a garden is good for our minds, bodies, and spirits. The landscapes that PHS designs and maintains around Philadelphia help ensure that everyone has access to spaces filled with plants and buzzing with life. At more than 10 sites, the PHS horticulture team has created beautiful, sustainable gardens that offer respite and inspiration to people while providing habitat for birds, insects, and other living things. At some of the locations, you can participate in caring for the gardens or, in the case of the popular Pop Ups, hang out with a cool beverage and a snack as you soak up the natural colors and scents around you. These PHS-maintained gardens are all open to the public at no cost.  

Logan Square and Swann Memorial Fountain

Benjamin Franklin Parkway and 19th Street

The long, gradual transformation of this space took a big step forward last fall, says Tom Morris, director of PHS Public Gardens and Landscapes. Woody plants, such as Cornus sanguinea ‘Midwinter Fire’ (a cultivar of bloodtwig dogwood), Ilex verticillata ‘Winter Gold’ (a winterberry cultivar), and Juniperus chinensis ‘Hetzii Columnaris’ (a green columnar Chinese juniper) have given the garden “backbones and structure,” he says. This season, the PHS horticulture team designed what he calls a “bright, crazy, colorful” display of annuals and tropicals that will bloom from spring into October.

Best time to visit: Check the PHS calendar for tours with a PHS horticulture pro and other events throughout the growing season.

Rodin Museum

Benjamin Franklin Parkway and 21st Street

Just a short walk from Logan Square, this home to the world-class sculpture collection is surrounded by a serene garden with a reflecting pool and beds full of bulbs, perennials, and small shrubs. In fall 2023, “we added to the border outside the fence,” Morris says, and “we specifically highlighted hydrangeas."

Best time to visit: Friday afternoons from May through August, when you can get a cocktail and sip it in the garden. 

Azalea Garden

Kelly Drive and Fairmount Avenue

Located between the Philadelphia Museum of Art and Boathouse Row, the Azalea Garden was established in 1952, sponsored by PHS to honor its 125th anniversary. Today, the landscape hosts more than 150 species of azaleas and rhododendrons, shaded by old oak, magnolia, and sycamore trees. “There’s been an ongoing effort to build up the understory, primarily with bulbs,” Morris says. In spring, you’ll see waves of crocuses, daffodils, tulips, and irises complementing the vivid blooms of the shrubs.

Best time to visit: The most extravagant blooming runs from May to early June.

Eastern State Penitentiary

Fairmount Avenue and North 22nd Street

Billed as “America’s first prison,” Eastern State is now a historic landmark and popular Halloween destination. The front terrace beds that PHS cares for are ever evolving, Morris says, and maintained by dedicated volunteers. Several other lots around the site have been transformed into vibrant green spaces for the community.

Best time to visit: Get your fingers in the dirt on a volunteer day and make new gardening friends along the way.  

LOVE Park

Arch and 15th Streets

The public square hosting the iconic sculpture has become a site for weddings and countless selfies, as well as a flower-filled oasis for Center City workers. “PHS designers have created borders of herbaceous shrubs and perennials, many of them natives.” Spring plantings of tropicals and annuals will dial up the floral color. “This is an all-season garden, and there’s something fresh happening from March through mid-October,” Morris says.

Best time to visit: Anytime you have a few moments when you’re in or around City Hall.

Delaware River Waterfront

Columbus Boulevard and Dock Street

In a partnership with the Delaware River Waterfront Corporation, PHS designs and maintains the variety of beds and borders along the 6 miles of developed recreational space between Port Richmond and Pennsport. At Spruce Street Harbor Park, the annuals and tropicals have been chosen in collaboration with a food vendor serving Puerto Rican cuisine to create a Caribbean-inspired garden.

Best time to visit: On spring and summer weekends starting at 11 a.m.

Pop Up Gardens

South and 14th Streets

The PHS Pop Up Garden on South Street is celebrating its 10th anniversary of bringing plants, food, and drink to a once-vacant lot in South Philadelphia. “It will have a lush garden feel this season,” Morris says. “The mixed borders will be full of native plants and other species that attract pollinators.”

Best time to visit: Check the calendar for plant swaps at both gardens so you can grow your collection or share with others.

Pop Up Gardens

Jamestown Avenue and Cresson Street

“Forest native” is the horticultural vibe at the PHS Pop Up Garden at Manayunk. Along with woodies (small trees and shrubs), “a mix of perennials and grasses have been chosen for interest all season long,” Morris says.

Best time to visit: Check the calendar for plant swaps at both gardens so you can grow your collection or share with others.

Philadelphia Navy Yard

South Broad Street and Constitution Avenue

The 1,200-acre site, maintained by PHS in partnership with the Philadelphia Industrial Development Corporation, hosts more than 2,000 trees, earning it certification as a Level 1 arboretum. Many of the beds are rain gardens, designed to help manage stormwater runoff. You can also see large pollinator gardens along Admiral Peary Way.

Best time to visit: The widest variety of flowers are in bloom in late spring and early summer, Morris notes.

Gateway Garden at Drexel

32nd and Market Streets

PHS has transformed this prominent spot, once an automobile repair shop, into an oasis of floral color in a busy area of the city. It has seating where you can relax in full sun or full shade while you take in the assortment of plants selected to represent the global connections of the Drexel student body.

Best time to visit: Workshops and tastings with beer and cider brewers introduce you to local producers as you bask in the garden. Look at the schedule for days and times.

Made in the Shade

A gardener found her vocation as she was creating her home landscape.

Like a lot of passionate gardeners, Carolyn Walker imagined leaving behind her office job to spend her days working with plants. More than 30 years ago, the Bryn Mawr resident shed her career as a lawyer and began collecting and selling uncommon shade plants. Today, Walker has become a respected expert on species that thrive where the sun doesn’t shine and a go-to resource for many other collectors and gardeners across the US and in Europe.

Walker’s early experiences with plants were less than inspiring to her. “My father was a big vegetable gardener, and I sometimes had to weed his beds and do other things that I did not enjoy at the time,” she says. She did like visiting the ornamental gardens of her aunt, Susie Walker, a renowned local horticulturist who is now the namesake for an award given to begonia exhibitors at the PHS Philadelphia Flower Show.

When Walker went to college, at Bowdoin College in Maine, her perspective changed. Her roommate tended many different types of houseplants, and “she taught me how to divide them and repot them with my hands,” Walker says. “I really loved that.” Over the next few years, Walker immersed herself in learning about houseplants, and then while living in an off-campus apartment, she began raising food in the backyard. “I was really into vegetable gardening. At one point, I grew 25 kinds of peppers and 36 tomatoes.”

NEW DIRECTION

Meanwhile, Walker completed law school and took a new job at a prominent Philadelphia firm. In 1983, she and her husband, Michael, moved back to Bryn Mawr, where she had been raised. “I practiced international corporate tax law,” she says. “I liked the work, but I didn’t care for the atmosphere. Being a lawyer is not a happy way to spend your time.”

Within a few years, Walker was looking for a way out. Her husband had secured a good job, and she told him, “I want to quit being a lawyer and find something that I like to do.” After contemplating the possibilities, she concluded that “what I really like to do is grow plants and to talk to people about plants.”

While continuing to work as an attorney, Walker took three horticulture courses at Temple University’s Ambler campus. As she was winding down her employment with part-time work in 1991 and launching her nursery business, she enrolled in the three-year horticulture program at the Barnes Foundation in Merion, Pennsylvania, and began the 16 courses necessary to complete both of Longwood Gardens’ certificate programs.

Walker was considering what direction to take with her love of plants when a friend noted that the couple’s property was shaded by many large trees, that many others in the area had shady landscapes, and that plants suitable for those conditions were hard to come by in local nurseries. In 1991, Carolyn’s Shade Gardens was launched. “I had three basic principles when I started the business: I didn’t want a greenhouse, I didn’t want to have any employees, and I wanted to do everything organically,” she says. She has never wavered on any of those principles, though Michael has played a key role in its success.

The terraced garden beds feature Cercis canadensis ‘Forest Pansy’, Heuchera ‘Caramel’, and Spiraea japonica ‘Walbuma’ on the upper level and Heuchera ‘Happy Flames’, Paeonia ‘Bartzella’, and Rosa ‘Westerland’ below the wall. In early spring, “this garden is not so much about flowers but about the echoes of the orange-red-gold in the leaves of the spiraea, heucheras, peonies, and rose,” Walker says.

The terraced garden beds feature Cercis canadensis ‘Forest Pansy’, Heuchera ‘Caramel’, and Spiraea japonica ‘Walbuma’ on the upper level and Heuchera ‘Happy Flames’, Paeonia ‘Bartzella’, and Rosa ‘Westerland’ below the wall. In early spring, “this garden is not so much about flowers but about the echoes of the orange-red-gold in the leaves of the spiraea, heucheras, peonies, and rose,” Walker says.

“Michael has been supporting me since the beginning, even when others said [the business] wouldn’t work,” she says. “He also has been doing most of the garden maintenance over the years, and he’s been working for CSG full-time since he retired in 2012.  I literally couldn’t do it without him, though I get all the credit.”

Carolyn’s Shade Gardens developed into a full-scale nursery, selling a wide variety of shade plants, including trees and shrubs, through catalogs, individual appointments, and popular open-house sales. “Our specialties were native plants, hellebores, hostas, snowdrops and other unusual bulbs, primroses, epimediums, and ferns,” she says. “Our customer list grew to 4,000 gardeners over the years, and our last spring catalog in 2019, which is still on our website, featured over 300 offerings.”

FINDING FOCUS

The business is in many ways an extension of the landscape Walker created around her and her husband’s home, a 2.2-acre lot in a residential neighborhood. It was part of a historic inn that was established in the 17th century. “We were attracted by the large trees here,” she says, gesturing to the towering London plane trees, oaks, walnuts, and tulip poplars overhead. “You can’t grow trees like these in your lifetime.”

When the couple moved in, the yard had been maintained strictly as a lawn. Walker went to work planting small flowering trees and creating beds and borders filled with plants that thrive in the shade. Today, the lawn has been replaced by a wide range of perennials and bulbs. On an early spring day, primroses, phlox, trilliums, and a ‘Yellow Bird’ magnolia are in vivid bloom.

A Prunus mume ‘Peggy Clarke’ (Japanese apricot tree) rises above the Lunaria annua ‘Variegata’, Dicentra spectabilis ‘Gold Heart’, and Viburnum plicatum f. plicatum ‘Popcorn’ that surround it.

A Prunus mume ‘Peggy Clarke’ (Japanese apricot tree) rises above the Lunaria annua ‘Variegata’, Dicentra spectabilis ‘Gold Heart’, and Viburnum plicatum f. plicatum ‘Popcorn’ that surround it.

As she filled her own place with plants, she nurtured a growing interest in Galanthus species and cultivars. “I took a bulb course in 1994 at Longwood with Charles Cresson,” a well-known Philadelphia gardener who became a mentor that she still checks in with frequently today. “I discovered that there were many interesting cultivars of snowdrops, and I started to seek out and grow the uncommon ones.” Walker also built up a collection of out-of-the-ordinary hellebores and hostas and now sells them, too. “I have all kinds of hostas, but I specialize in the miniature ones,” she says while pointing to a grouping of “mouse ear” varieties in a planter.

In 2009, she put together a catalog of her varieties and began to sell them through the mail. Her reputation among galanthus enthusiasts grew and her catalog now goes out to gardeners throughout the mid-Atlantic region and as far away as the Pacific Northwest, northern Maine, Minnesota, and Georgia. All sales are preorders, which tend to sell out quickly. “I’ve had as many as 150 orders in the first hour” after her online catalog is launched for the year, she says.

LOOKING AHEAD

Over the years, Walker’s business grew larger and more successful until it became too much for her and her husband to run by themselves.  “In 2019, I said to my husband that something had to go, but we couldn’t decide what it was,” she recalls. Then came the COVID pandemic. She and Michael spent the early days of spring 2020 doing “no contact” deliveries of hellebores to people in the region who had ordered them and now couldn’t pick them up due to the shutdown. “We were cut back from a lot of what we had been doing, and we decided it wasn’t ideal, but it worked for us,” she says. “So we started to just market snowdrops, hellebores, and hostas by pre-order from catalogs.  Snowdrops are shipped, while hellebores and hostas are picked up at the nursery.”

With help from Michael, Walker has been tending all the plants and processing hundreds of orders by herself. At the same time, she continues to add plants, including many native species, to their landscape. She has hosted tours in the past from local gardening groups and has done media appearances. Walker’s detailed blog posts on shade plants have had almost 3.5 million views by readers from more than 150 countries. “When I go to England to visit snowdrop suppliers and venues, they have always read my articles on snowdrops,” she notes. 

The area beneath an old Platanus x acerifolia, or London plane tree, and a Cercis canadensis f. alba ‘Royal White’ in bloom is carpeted with native perennials including Asarum candense, Stylophorum diphyllum, Packera aurea, Podophyllum peltatum, and Mertensia virginica.

The area beneath an old Platanus x acerifolia, or London plane tree, and a Cercis canadensis f. alba ‘Royal White’ in bloom is carpeted with native perennials including Asarum candense, Stylophorum diphyllum, Packera aurea, Podophyllum peltatum, and Mertensia virginica.

Now the mother of three adult sons is considering ways to sustain the business into the future. When asked about this, she breaks into a coy smile and says, “Plans are in the works to expand the offerings to a full range of shade plants, including woodies.” Whatever direction the plans take, Walker will stick to her commitment to “only sell what I know from experience will perform well for home gardeners.”

Learn more about snowdrops and other shade-loving species at Carolyn’s Shade Gardens blog.

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Made in the Shade

A gardener found her vocation as she was creating her home landscape.

Like a lot of passionate gardeners, Carolyn Walker imagined leaving behind her office job to spend her days working with plants. More than 30 years ago, the Bryn Mawr resident shed her career as a lawyer and began collecting and selling uncommon shade plants. Today, Walker has become a respected expert on species that thrive where the sun doesn’t shine and a go-to resource for many other collectors and gardeners across the US and in Europe.

Walker’s early experiences with plants were less than inspiring to her. “My father was a big vegetable gardener, and I sometimes had to weed his beds and do other things that I did not enjoy at the time,” she says. She did like visiting the ornamental gardens of her aunt, Susie Walker, a renowned local horticulturist who is now the namesake for an award given to begonia exhibitors at the PHS Philadelphia Flower Show.

When Walker went to college, at Bowdoin College in Maine, her perspective changed. Her roommate tended many different types of houseplants, and “she taught me how to divide them and repot them with my hands,” Walker says. “I really loved that.” Over the next few years, Walker immersed herself in learning about houseplants, and then while living in an off-campus apartment, she began raising food in the backyard. “I was really into vegetable gardening. At one point, I grew 25 kinds of peppers and 36 tomatoes.”

NEW DIRECTION

Meanwhile, Walker completed law school and took a new job at a prominent Philadelphia firm. In 1983, she and her husband, Michael, moved back to Bryn Mawr, where she had been raised. “I practiced international corporate tax law,” she says. “I liked the work, but I didn’t care for the atmosphere. Being a lawyer is not a happy way to spend your time.”

Within a few years, Walker was looking for a way out. Her husband had secured a good job, and she told him, “I want to quit being a lawyer and find something that I like to do.” After contemplating the possibilities, she concluded that “what I really like to do is grow plants and to talk to people about plants.”

While continuing to work as an attorney, Walker took three horticulture courses at Temple University’s Ambler campus. As she was winding down her employment with part-time work in 1991 and launching her nursery business, she enrolled in the three-year horticulture program at the Barnes Foundation in Merion, Pennsylvania, and began the 16 courses necessary to complete both of Longwood Gardens’ certificate programs.

Walker was considering what direction to take with her love of plants when a friend noted that the couple’s property was shaded by many large trees, that many others in the area had shady landscapes, and that plants suitable for those conditions were hard to come by in local nurseries. In 1991, Carolyn’s Shade Gardens was launched. “I had three basic principles when I started the business: I didn’t want a greenhouse, I didn’t want to have any employees, and I wanted to do everything organically,” she says. She has never wavered on any of those principles, though Michael has played a key role in its success.

The terraced garden beds feature Cercis canadensis ‘Forest Pansy’, Heuchera ‘Caramel’, and Spiraea japonica ‘Walbuma’ on the upper level and Heuchera ‘Happy Flames’, Paeonia ‘Bartzella’, and Rosa ‘Westerland’ below the wall. In early spring, “this garden is not so much about flowers but about the echoes of the orange-red-gold in the leaves of the spiraea, heucheras, peonies, and rose,” Walker says.

The terraced garden beds feature Cercis canadensis ‘Forest Pansy’, Heuchera ‘Caramel’, and Spiraea japonica ‘Walbuma’ on the upper level and Heuchera ‘Happy Flames’, Paeonia ‘Bartzella’, and Rosa ‘Westerland’ below the wall. In early spring, “this garden is not so much about flowers but about the echoes of the orange-red-gold in the leaves of the spiraea, heucheras, peonies, and rose,” Walker says.

“Michael has been supporting me since the beginning, even when others said [the business] wouldn’t work,” she says. “He also has been doing most of the garden maintenance over the years, and he’s been working for CSG full-time since he retired in 2012.  I literally couldn’t do it without him, though I get all the credit.”

Carolyn’s Shade Gardens developed into a full-scale nursery, selling a wide variety of shade plants, including trees and shrubs, through catalogs, individual appointments, and popular open-house sales. “Our specialties were native plants, hellebores, hostas, snowdrops and other unusual bulbs, primroses, epimediums, and ferns,” she says. “Our customer list grew to 4,000 gardeners over the years, and our last spring catalog in 2019, which is still on our website, featured over 300 offerings.”

FINDING FOCUS

The business is in many ways an extension of the landscape Walker created around her and her husband’s home, a 2.2-acre lot in a residential neighborhood. It was part of a historic inn that was established in the 17th century. “We were attracted by the large trees here,” she says, gesturing to the towering London plane trees, oaks, walnuts, and tulip poplars overhead. “You can’t grow trees like these in your lifetime.”

When the couple moved in, the yard had been maintained strictly as a lawn. Walker went to work planting small flowering trees and creating beds and borders filled with plants that thrive in the shade. Today, the lawn has been replaced by a wide range of perennials and bulbs. On an early spring day, primroses, phlox, trilliums, and a ‘Yellow Bird’ magnolia are in vivid bloom.

A Prunus mume ‘Peggy Clarke’ (Japanese apricot tree) rises above the Lunaria annua ‘Variegata’, Dicentra spectabilis ‘Gold Heart’, and Viburnum plicatum f. plicatum ‘Popcorn’ that surround it.

A Prunus mume ‘Peggy Clarke’ (Japanese apricot tree) rises above the Lunaria annua ‘Variegata’, Dicentra spectabilis ‘Gold Heart’, and Viburnum plicatum f. plicatum ‘Popcorn’ that surround it.

As she filled her own place with plants, she nurtured a growing interest in Galanthus species and cultivars. “I took a bulb course in 1994 at Longwood with Charles Cresson,” a well-known Philadelphia gardener who became a mentor that she still checks in with frequently today. “I discovered that there were many interesting cultivars of snowdrops, and I started to seek out and grow the uncommon ones.” Walker also built up a collection of out-of-the-ordinary hellebores and hostas and now sells them, too. “I have all kinds of hostas, but I specialize in the miniature ones,” she says while pointing to a grouping of “mouse ear” varieties in a planter.

In 2009, she put together a catalog of her varieties and began to sell them through the mail. Her reputation among galanthus enthusiasts grew and her catalog now goes out to gardeners throughout the mid-Atlantic region and as far away as the Pacific Northwest, northern Maine, Minnesota, and Georgia.  All sales are preorders, which tend to sell out quickly. “I’ve had as many as 150 orders in the first hour” after her online catalog is launched for the year, she says.

LOOKING AHEAD

Over the years, Walker’s business grew larger and more successful until it became too much for her and her husband to run by themselves.  “In 2019, I said to my husband that something had to go, but we couldn’t decide what it was,” she recalls. Then came the COVID pandemic. She and Michael spent the early days of spring 2020 doing “no contact” deliveries of hellebores to people in the region who had ordered them and now couldn’t pick them up due to the shutdown. “We were cut back from a lot of what we had been doing, and we decided it wasn’t ideal, but it worked for us,” she says. “So we started to just market snowdrops, hellebores, and hostas by pre-order from catalogs.Snowdrops are shipped, while hellebores and hostas are picked up at the nursery.”

With help from Michael, Walker has been tending all the plants and processing hundreds of orders by herself. At the same time, she continues to add plants, including many native species, to their landscape. She has hosted tours in the past from local gardening groups and has done media appearances. Walker’s detailed blog posts on shade plants have had almost 3.5 million views by readers from more than 150 countries. “When I go to England to visit snowdrop suppliers and venues, they have always read my articles on snowdrops,” she notes. 

The area beneath an old Platanus x acerifolia, or London plane tree, and a Cercis canadensis f. alba ‘Royal White’ in bloom is carpeted with native perennials including Asarum candense, Stylophorum diphyllum, Packera aurea, Podophyllum peltatum, and Mertensia virginica.

The area beneath an old Platanus x acerifolia, or London plane tree, and a Cercis canadensis f. alba ‘Royal White’ in bloom is carpeted with native perennials including Asarum candense, Stylophorum diphyllum, Packera aurea, Podophyllum peltatum, and Mertensia virginica.

Now the mother of three adult sons is considering ways to sustain the business into the future. When asked about this, she breaks into a coy smile and says, “Plans are in the works to expand the offerings to a full range of shade plants, including woodies.” Whatever direction the plans take, Walker will stick to her commitment to “only sell what I know from experience will perform well for home gardeners.”

Learn more about snowdrops and other shade-loving species at Carolyn’s Shade Gardens blog.

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Time Share

Local residents work together to bring a bounty of fresh food to their neighbors.

Volunteers at the PHS Green Resource Center help prepare vegetable plants for distribution to community gardeners.

Volunteers at the PHS Green Resource Center help prepare vegetable plants for distribution to community gardeners.

On the day before spring begins, the PHS Green Resource Center in the Strawberry Mansion neighborhood is bustling with activity. Inside, Emma Ford and Sybria Deveaux, from PHS, and an enthusiastic band of volunteers are potting up cool-season crops, including broccoli and kale, providing the little plants with more spacious containers to give their roots room to grow. The seedlings are destined for community gardens and other growers who have committed to helping to increase access to fresh produce in our region through the PHS City Harvest program.

The plants may be tiny, but the undertaking is huge. In 2024, PHS will distribute approximately 275,000 seedlings, which include about 30 different crops with 160 different cultivars, says Ford, propagation manager of the PHS City Harvest program. Many of the varieties are chosen for their cultural value to gardeners such as the refugees from Myanmar and Bhutan in South Philadelphia. Urban farmers that provide food to their neighbors can request large quantities of seedlings from PHS. Heritage Farm in West Philadelphia is one such participant.

Click on the video below to meet some of the volunteers.

The effort to grow all the seedlings takes months of planning and preparation by PHS staff. About 140 volunteers also play a vital role in the process, Ford says. “Access to fresh food is centered on community building,” she tells us. “Without volunteers and community support, we would not be able to execute our impact or engage as many people as possible in our programming!”

For the people who contribute their time in the greenhouse, the rewards tend to be both personal and communal. “I have a community garden, and I help out at Sanctuary Farm,” says local resident Nia Dixon. “I raised my kids around the community garden at 21st and Dauphin.” She adds that working with plants and supporting neighbors makes her feel complete. “At the end of the day, we all got to eat, and contrary to what some young people today think, food doesn’t grow in a store.”

“These seedlings are going to produce food, and that’s exciting.”

Finding like-minded people is important to Dimitri Cugini. “I love giving back to the community, and I love gardening,” he says. “Volunteering with PHS is a way for me to do both. I’m new to this area, and this is a good way to meet people who share my interests.”

Kera Gibbs, who recently joined PHS as a Healthy Neighborhoods specialist, enjoys working with plants but is focused on the end results. “These seedlings are going to produce food, and that’s exciting. We’re starting a farmers’ market for Nicetown–Tioga, and along with the food, we plan on offering plants to gardeners so they can grow their own.”

For Sarah Moser, time spent in the greenhouse is therapeutic. “I live in an apartment, so I don’t get enough ‘dirt’ time,” she says. “Working with these plants is a connection to the earth. It’s calming and peaceful. It’s cultivating life!”

If this sounds like a good time to you, PHS offers a wide range of opportunities to get your hands dirty while helping to bring the benefits of gardening to all. You can assist with caring for public landscapes, planting trees across the city, harvesting crops at Norristown Farm Park or Bartram’s Garden, and more. Check the schedule for all the details.

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Above: Amsonia hubrichtii flowers in late May at Chanticleer.

ABOUT AMSONIA

FAMILY Apocynaceae (dogbane)
GENUS Amsonia
SPECIES Most of the 22 recognized species are native to North America. Two sometimes found in US nurseries are not native: A. orientalis (originating in Greece and Turkey) and A. elliptica (from East Asia).
USES Perennial borders, pollinator beds, rock gardens, and containers
GROWING CONDITIONS Full sun to partial shade; different soil types
HELPFUL HINT Amsonias are clump-forming plants with deep root systems and semiwoody stems that make them difficult to divide or move once they are established. Growing new ones from seed, however, does not require expertise or special equipment.

Amsonia tabernaemontana is a native in our region.

Amsonia tabernaemontana is a native in our region.

If you made a list of the attributes that you’d want in the ideal perennial for your garden, it would probably start with the ability to produce clusters of colorful, fragrant blooms that last for weeks. You’d like foliage that’s attractive in fall. The perennial should thrive in full sun to partial shade and in a wide range of soil types. It would be a native plant that provides nectar and habitat to bees, butterflies, and hummingbirds. Your perfect perennial should require little maintenance once established and be long-lived so you don’t have to replace it every few years. And it should be resistant to attacks from marauding deer; otherwise these other positive qualities don’t even matter.

If finding a plant with so many appealing traits seems unrealistic, let us introduce you to the members of the genus Amsonia, commonly known as bluestars. Most of the 22 recognized species are native to North America. At Mt. Cuba Center, the native plant garden and research center in Hockessin, Delaware, a team of scientists and horticulturists evaluated 20 different Amsonia species and cultivars from 2013 to 2023 and shared their results in February 2024. We checked in with Sam Hoadley, manager of horticultural research at Mt. Cuba Center, for his recommendations and insights on choosing and using bluestars in your garden.

WINNING WAYS

Amsonias open their sprays of pale-blue-to-periwinkle, star-shaped blooms in mid to late spring, and they last into early summer. Their scent is often described as “spicy.” The flowers attract the native bees that are active early in the season. As the weather heats up, the flowers fade away, and the rich, green foliage becomes the main attraction. The leaves may range from willowlike to feathery, depending on the species. In fall, the foliage becomes a buttery-gold or vibrant-orange color.

Throughout the season, the plants host several species of butterflies and moths, including the snowberry clearwing moth (Hemaris diffinis), according to the Mt. Cuba Center researchers. Like milkweeds (Asclepias) and other members of the Apocynaceae family, amsonia plants produce a milky sap that discourages browsing by deer and other pesky mammals.

Bluestars grow well in clay or sandy soil and even tolerate moist conditions. The foliage achieves its richest fall color in full sun, but the plants live and bloom well in partial shade too.

TOP PERFORMERS

Named for the 18th-century Virginia physician and botanist John Amson, amsonias grow uncultivated in many areas of the United States and Mexico. Two non-native species that may be available in nurseries in our region originated in Greece and Turkey (Amsonia orientalis) and East Asia (A. elliptica). Three widely adapted native species, A. ciliata, A. hubrichtii, and A. tabernaemontana, along with many of their cultivars and hybrids, were the subject of the Mt. Cuba trials. “All of them performed very well in a variety of conditions,” Hoadley says. “That means you can choose which is best for your garden based on your preferences for size and foliage texture.”

Bluestars commonly reach 3 feet tall at maturity. If your space is limited, consider A. ciliata var. tenuifolia, a cultivar of fringed bluestar. It grows 15 to 24 inches tall and wide. “It looks similar to the popular A. hubrichtii but stays a fraction of the size,” Hoadley says. “You can use it in any tight space, including rock gardens and ‘hell strips’ (the narrow spaces between the sidewalk and street in many neighborhoods). It will fit nicely into a large container too.” Another option, A. tabernaemontana ‘Short Stack’, tops out at 10 inches high.

MINIMAL MAINTENANCE

As with other long-lived perennials, bluestars take time to get established before they show their full potential for flowers, foliage, and fall color. “You need to have a little patience after you plant amsonias. They can take three years to show off their mature qualities, but after that, they really come on strong,” Hoadley says. “Over the 10 years of our trial, the plants looked better every year.”

The only attention amsonias need is an annual trimming in late winter to cut back the previous season’s stems. Hoadley recommends leaving 12 to 18 inches of stems standing because they are hollow and provide habitat for native bees.

Bluestars are not invasive in home gardens, Hoadley says, but “they are very promiscuous. If you have more than one species in your home garden, it is likely that hybrids will sprout up. The chance seedlings can be quite nice.” Unwanted plants are easy to weed out before they get established.

STYLE POINTS

Amsonias are big and dramatic enough to work in drifts of three to five plants in a wide border. Or add them to a bed full of plants that attract and sustain pollinators, the essential workers of our ecosystem.

The light-blue color of amsonia flowers in spring matches well with purples and yellows, Hoadley says. Sunny wood poppy (Stylophorum diphyllum) and lavender Jacob’s ladder (Polemonium reptans) plants bloom around the same time as bluestars and create a “lovely combination” in Hoadley’s home garden as well as at Mt. Cuba Center. The airy foliage of amsonias provides a “beautiful textural contrast to wide-leaved perennials,” he says.

Wherever you plant amsonias, you can count on them for years to come. “I’m convinced that if a bluestar is in the right site, it would outlive us,” Hoadley says. That sounds ideal, doesn’t it?

See the complete report on the amsonia trials at Mt. Cuba Center. A. hubrichtii was named a PHS Gold Medal Plant in 2014. To learn more about it and other plants evaluated for their performance in our region, check out the PHS Gold Medal Plant Database.

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In spring, the soft blue flowers of amsonia pair well with alliums like this Nectaroscordum siculum.

In spring, the soft blue flowers of amsonia pair well with alliums like this Nectaroscordum siculum.

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