By Andrew Bunting, PHS VP of Horticulture 

With the changing climate, gardens face increasing challenges from episodes of heavy rainfall and prolonged droughts. Keeping your garden thriving during the summer, especially when you're away, requires a solid plan for watering and moisture conservation. Here’s how you can ensure your garden stays lush and healthy while you’re on vacation. 

How Long Can Plants Go Without Water? 

When preparing for vacation, many gardeners wonder how long their plants can survive without water before they begin to dry out or die. This depends on the plant types, garden light conditions, and weather. Plants in shaded areas may last longer without water compared to those in full sun. Container and window box plants can dry out in a day, whereas many houseplants can manage with one watering per week or less. 

How to Water Plants While Away 

Before You Leave 

• Deep Watering: If it hasn’t rained recently, water your garden thoroughly with a sprinkler, especially a wide-covering, oscillating type. This will help saturate the soil before you go. 

While You Are Away 

• Timed Sprinklers: For absences longer than a week, place sprinklers with timers set to water every 3-4 days. 
• Drip Irrigation Systems: Install drip irrigation with timers to ensure containers and window boxes receive regular watering. 
• Gardener’s Help: If possible, have a friend or neighbor check on your garden and water as needed. 

Don’t Forget the Houseplants! 

• Deep Watering: Deep watering houseplants before you leave for a vacation should provide them with enough moisture while you are away. 
• Extra Moisture: For those plants that consume a lot of moisture, you can sit the plant in a plant saucer and add a little water as a backup. 

Mulching for Moisture Conservation 

Whether you’re planning a summer vacation where you’ll be away from your garden, or simply want to help your garden contend with tough summer conditions, mulching helps suppress weeds, add organic matter to the soil, and conserve moisture. Here are some types of mulch to consider: 

• Leaf Compost: Semi-composted leaves are often available through municipalities, sometimes mixed with other composted materials. 
• Shredded Bark Mulch: Byproducts of various timber industries,  these last most of the growing season, but can also dry out quickly. 
• Composted Chips: When an arborist sends branches through a chipper, it creates wood chips of various lengths and sizes that are best used after aging for a year to avoid nutrient depletion. These are especially helpful around the base of trees to help conserve moisture during the summer. 
• Leaves: "Leave the Leaves" involves using fall leaves as mulch, which is excellent for overwintering beneficial insects and pollinators. 

Right Plant, Right Place 

Choosing the right plants for the right conditions in your garden can make summer maintenance easier, especially while you travel. Make sure to select the right kinds of plants for your sunlight conditions to minimize watering! 

Shade-Loving Plants 

Planting plants in shade or partial shade will create gardens that are much less vulnerable to drying out during periods of drought and heat stress, making it easier to maintain your garden while traveling or while contending with hot, dry conditions. 

• The Foam Flower, Tiarella: 'Brandywine' is a PHS Gold Medal Plant selection with clumping foliage, spikes of white flowers in the spring, and semi-evergreen leaves. 
• Wood Aster, Eurybia divaricata: Tolerates shade and blooms with tiny white flowers in the early fall. ‘Eastern Star’ is an outstanding selection. 
• Christmas Fern (Polystichum acrostichoides): Adaptable to rocky, dry soils with upright evergreen fronds. 

The following plants are especially good for dry shade: 

• Epimedium: Early spring flowering perennial that thrives in dry shade. These exquisite flowers appear before the plant's foliage and there are species and cultivars in red, pink, purple, white and orange. This colonizing perennial grows in deep shade and needs minimal amounts of moisture. 
• Helleborus: The Lenten rose and Christmas rose, as well as other species of Helleborus have evergreen leaves and will start blooming around the end of the year and into March. The cup-shaped flowers are one of the best flowering plants for the winter months, but also thrive in dry shade in the summertime.  

Sun, Heat, and Drought-Tolerant Plants 

Many of the plants native to the Midwestern prairies are excellent for hot dry conditions due to their taproots. During dry periods, when the soil surface is parched and lacks moisture, tap roots can extend deeper into the ground to access water reserves. 

• Coneflowers (Echinacea): The purple coneflower, Echinacea purpurea has dozens of cultivars including ‘Magnus’ and ‘Pica Bella.’  Echinacea paradoxa has yellow flowers and the popular pale coneflower, Echinacea pallida has soft pink reflexed flowers.  The coneflowers attract pollinators and are a great seed source for native finches, sparrows and the American Goldfinch in late summer and fall. 
• Beebalms (Monarda): Many species of Monarda can take dry conditions including Monarda punctata and Monarda bradburiana. All the beebalms are deer-resistant and excellent pollinator hosts. 
• Ornamental Grasses: There are many prairie natives that are also ornamental grasses including the prairie dropseed, Sporobolus heterolepis; little bluestem, Schizachyrium scoparium; big bluestem, Andropogon gerardii and switchgrass, Panicum virgatum. All are noted for their upright, architectural foliage that often has great fall color and winter interest. 
• Cactus and Succulents: Throughout the United States there are many native cactus and succulents that are extremely tolerant of the heat and drought, such as Opuntia and Cylindropuntia. Additionally, Adam’s Needle-Yucca is a desert-like plant with very upright and sharp leaves and a towering flower stem with white flowers. Some of these species include Yucca filamentosa, Y. gloriosa and Y. brevifolia. 

While heat and drought can be a challenge in the garden during summer, keeping your garden thriving and looking its best can be simple if you select the right plants for the right places, and develop watering and maintenance habits that help preserve moisture for longer. When preparing to travel, one of the simplest ways to keep a garden watered and looking great is to set up timed sprinklers, utilize mulch where possible, and tap in a neighbor or friend to help keep up with watering in your absence. With these tips in mind, you can leave for your next vacation or simply enter this summer season feeling confident your garden will continue to thrive.