Fall Blooming Perennials

By Andrew Bunting, PHS Vice President of Horticulture

October is one of my favorite times of the year in the garden.  Many annuals and tropical plants are peaking in their interest and will look great right up to the first significant frost. These displays are often enhanced by the myriad of fall blooming perennials which are just coming into flower now. 

Nothing is more of an iconic fall flowering perennial than the asters. There are literally dozens of species and cultivars that have an abundance of flowers ranging from white to blue to pink. Recently, I saw plantings of two of my old favorites. The Tatarian aster, Aster tataricus is a robust growing aster that quickly expands to large masses in the garden. The gardener needs to be aware that this aster can be aggressive in the garden. However, it also has an amazing abundance of stout stems reach six feet tall covered in lavender, small, daisy-like flowers with a yellow center. ‘Jindai’ is a more diminutive form. On a recent visit to the Scott Arboretum, I was reacquainted with an old favorite selection of the New England aster, Symphyotrichum novae-angliae ‘Andenken an Alma Potschke’. At maturity it reaches three to five feet tall and has a bushy habit covered in cerise flowers with a yellow center. 

An exotic looking addition to the fall garden are the toadlilies, Tricyrtis.  Tricyrtis hirta, is the common toad lily with orchid-like with uppward facing white flowers specked with purple spots that line the arching branches. ‘Sinonome’ is more upright with sprays of purple flowers with darker purple spotting.  Tricyrtis ‘Amanowgawa’ (syn. ‘Milky Way’) has arching stems with creamy white flowers and Tricyrtis macrantha subsp. macranthopsis have very arching stems with glossy leaves that are adorned with exquisite tubular yellow flowers. This toad lily is best displayed where the arching aspect can be highlighted such as hanging over a wall. Toad lilies thrive in partial sun to a fair amount of shade in the garden.

A very architectural fall blooming perennial is the bold foliaged Kirengeshoma palmata. This shade perennial can reach five feet tall. It has soft butter yellow teardrop-like buds that open to a tubular flower.

A rarity, is Rabdosia longituba (syn. Plectranthus longituba), trumpet spurflower has long cascading stems that are covered in tubular deep violet flowers. It is a great perennial to spill over or twine through other perennials or ornamental shrubs.

One of my favorites for the fall is the bush clover, Lesepedeza thunbergii ‘Gibraltar’.  This sun loving perennial is as “tough as nails”. It can grow in fall sun with arid condition and poor soils and not miss a beat. This fine textured, shrub-like perennial has a billowing habit to six feet all and an equal width that becomes covered in pea-like magenta flowers in mid-October. Lespedeza looks great in combination with purple foliaged shrubs like Cotinus coggygria ‘Velvet Cloak’ and Physocarpus opulifolius Summer Wine®.

The windflower, Anemone x hybrida is aptly named.  The slender wiry stems have great motion in the gardens as they sway in the slightest breeze. Rising above the basal foliage are an abundance of stems covered in buttercup-like flowers.  ‘Honorine Jobert’ has single white flowers. ‘Whirlwind’ has double flowers and ‘September Charm’ has soft pink flowers with a yellow center.

Finally, the hardy begonia, Begonia grandis is a wonderful addition to the fall garden.  In the spring it is one of the last perennials to emerge. It comes up so late I often wonder if it is alive. The dark green leaves  have dark red netted veins on their undersides. They are adorned with bubblegum pink flowers in profusion starting in the early fall and are then followed by interesting pink seed capsules. This spreading perennial also seeds throughout the garden and serendipitously seems to pop up in all the right places. There is also a white selection, ‘Alba’.