by Henry Homeyer
CORNISH FLAT, N.H. – Many gardeners go to the plant nurseries in June, and buy things in bloom for their gardens and rarely go back until the next year. But that means that now, as summer winds down, they have few flowers in bloom. Not me. I buy perennials in all seasons. Fall flowers are important not only for me, but for those monarch butterflies that need to have plenty of hefty meals before taking off for Mexico.
Many of the flowers that bloom in fall are tall wild flowers that have been tamed, and made into garden flowers: many of the fall asters, Joe Pye weed and Rudbeckias (black-eyed Susans) sold in nurseries were just selected and bred to be more garden-worthy.
According to entomologists in the know, the best plant for pollinators in fall is the goldenrod (Solidago spp.). This tall beauty has a bad reputation in some circles as a few species of goldenrod are a bit aggressive, arriving uninvited and spreading like crazy by root. And since they have massive root systems, they are not easy to remove. But not all are like that, and some are being sold in nurseries.
One of my favorite goldenrods is “Fireworks.” I’ve had it about 10 years and it is not at all a thug. The original plant has gotten bigger every year, but never to the point of causing problems. It blooms in September with sprays of dainty yellow flowers in a vase-like arrangement. It is readily available in nurseries. It stands three- to four-feet tall.
I also grow one called blue-stemmed goldenrod (Solidago caesia) that is a shade- loving, diminutive goldenrod that I bought at the Garden in the Woods in Framingham, Mass., many years ago. It is perfectly well behaved: it stays in a tidy clump and blooms late in the fall. It’s only about 16 inches tall.
New York Ironweed (Vernonia noveboracensis) is a great pollinator plant that stands four to six feet tall or more with purple aster-like blossoms in big clusters. It does best in full sun and moist soil. Because it is such a tall plant once established, it is recommended that you cut it back to the ground when it is two feet tall in early summer to get a more manageable size. I wouldn’t do that until year two or three. And don’t give it fertilizer at planting time, or it may flop. Monarchs just love this plant, as do a myriad of bees.
New England asters (now no longer with the scientific genus name of aster, but Symphyotrichum) come in many sizes and a few colors. The wild ones are great. I have them alongside my stream in a light lavender. But commercially available ones come in pink and purple, too. They vary in height from quite short (often sold in bloom with the chrysanthemums) to over five feet tall. The mum-sized ones get taller in year two and after, as they are cut back repeatedly to increase the number of blossoms and to keep them short. Full sun is best for these; they will grow in ordinary garden soil.
Joe Pye weed (Eutrochium spp., formerly Eupatorium) is also beloved by monarchs and pollinators of all kinds. The native Joe Pye grows wild along my stream, but I also have it growing in a garden bed I call the “Darwin bed.” The Darwin bed never gets weeded, and tall flowers fight for space. That bed contains Joe Pye, turtle head, asters, goldenrod, and giant fleece flower, among others.
The variety in the Darwin bed is one called “Gateway.” Instead of greenish stems, it has dark purple-black stems, and grows even taller than the native species. Mine is nearly eight feet tall growing in moist, rich soil. All kinds have pink-to-purple flowers in large panicles at the tops of stems, sometimes a foot or more across.
There is a smaller version of Joe Pye weed, one called “Baby Joe” that has been bred to be smaller, allegedly two to three feet tall. But I hear it is more like three to four feet tall if pleased with where it is situated. All have very tenacious root systems, so plant it where you want it.
Of my favorites is loved by bumblebees but the nectar and pollen is unavailable to monarchs because the blossoms are tightly closed. Turtlehead (Chelone lyonii) has clusters of delightful pink blossoms atop four-foot stems. The flowers are unlike anything else I grow. They resemble the head of a turtle, and bumblebees force their way in through the “mouth” of the turtle. If you listen, sometimes you can hear the bees inside, almost growling. Or are they purring? I don’t know.
Turtlehead has a long bloom time and is a great cut flower. They start blooming in August and bloom though much of September. They do best with rich, moist soil but I have them in full sun as well as full shade. There is another turtlehead that is white, but much less vigorous for me. Its Latin name is C. glabra and I have rarely seen it for sale in a nursery.
A real delight for me is to have a few bulb plants that bloom in the fall. Fall crocus is actually not a crocus at all, but a species known as Colchicum autumnale. It has leaves in the spring which disappear in summer, then it surprises us with big crocus-like blossoms on four-inch stems. The flowers come in singles and doubles in colors from white to pink to purple. Expensive, but worth it. Most reliable in Zone 5 or warmer, though I have it in Zone 4. The flowers are on dainty stems, and often flop over unless planted in a ground cover like Vinca that helps hold the flowers up.
So go to your plant nursery now and see what you can get that blooms in the fall. Our pollinators need food now, too.