To mention landscaping for fall color, we might think about the showy display that the foliage of many trees and shrubs provides. In Northeast Texas, many woody plants can put on a decent show most years, but elsewhere in Texas fall foliage is not that noteworthy. But there are many flowering plants that wait for fall to flaunt their floral display, while others start flowering in the summer and keep on going right up to fall frost.
I like to mainly use perennial plants in my yard, ones that come back every year, which usually get bigger and better each succeeding year. It is fun to have something in bloom in our yards throughout the year, and by having a mix of spring, summer and fall-blooming plants, you can have a landscape that is not only beautiful but also beneficial to pollinators. Here are several plants to consider if you would like to have an abundance of flowers in the fall.
FLOWERS FOR SHADE
In the September/October 2021 issue of Texas Gardener, I wrote about four fall-blooming perennials for shady spots in the yard. Those included Turk’s cap (Malvaviscus arboreus var. drummondii), toad lilies (Tricyrtis spp.), firespike (Odontonema strictum) and leopard plant (Farfugium japonica). I have also written about fall-blooming azaleas that provide a burst of color as the days shorten.
There are several perennials that bloom in response to longer nights after we pass the fall equinox. Something within these plants triggers them to initiate floral buds and begin to grow. This phenomenon is called photoperiodism, and plants that respond to longer dark periods are called “short-day plants.”
Garden mums are a classic example of this trait. This was first described in 1920 by two scientists investigating the late-blooming habit of a particular tobacco variety. There are many other plants that bloom in the fall, and while scientists are still investigating what physiological factors are involved, gardeners only need to be aware to not plant short-day plants near streetlights or security lights that come on at night.
Several years ago, I was gifted with a wonderful bush clover called ‘Little Volcano’ (Lespedeza thunbergia ‘Little Volcano’). I knew it bloomed in the fall on cascading stems covered with purple flowers, but it didn’t occur to me that it was photoperiodic. Across the street from where I planted it was a streetlight. For several years, it mainly bloomed on the side facing away from the light, and it finally occurred to me that the street-light was significantly inhibiting floral display. I gifted it to some neighbors, warning them to plant it away from lights, where it now flowers abundantly.
FLOWERS FOR SUN
A delightful marigold relative called Mexican mint marigold (Tagetes lucida) waits until October to cover itself with small, bright-yellow flowers. This popular perennial is also used as an herb to substitute for French tarragon. Another marigold relative is Copper Canyon daisy (Tagetes lemmonii), a tough, drought-tolerant, native shrubby perennial of the Southwest that also gets covered with golden-yellow flowers in the fall.
Salvias are great perennials for Texas, and while many of them bloom from spring right through to the first freeze, some species wait until late summer and fall to put on their main show. A popular fall-blooming salvia is Mexican bush sage (Salvia leucantha). It has attractive foliage from spring through fall, when it is topped with long spikes sporting flowers with fuzzy purple calyces and either white or purple corollas. There are several varieties on the market, including the more compact selection ‘Santa Barbara’.
Mountain sage and Mexican darcy sage (Salvia regla and S. darcyi) are two other salvias that have some blooms in the early summer but cover themselves in the fall with loads of bright-red tubular flowers — a hummingbird delight. ‘Golden Delicious’ pineapple sage (Salvia elegans ‘Golden Delicious’) provides chartreuse foliage topped with spikes of bright-red flowers during late summer through fall.
All the above perennials are best grown in mostly full sun and in soils with good drainage, though pineapple sage might prefer some afternoon shade to prevent leaf scorch.
In the Heritage Rose Garden in the Tyler Botanical Garden there is a delightful combination of the exceptional passalong mum ‘Country Girl’ and a fall-blooming aster (now genus Symphyotrichum; formerly Aster oblongifolius). The pale pink flowers of the mum make a perfect companion with the abundant darker purple aster flowers every fall.
As migrating Monarch butterflies make their way back every fall to their wintering grounds in Mexico, they need a supply of nectar-producing flowers along their long route. One exceptional perennial whose flowers are always covered with Monarch, Queen and other butterflies is Gregg’s mistflower (Conoclinium greggii). This fabulous butterfly magnet, native to the Southwest, begins blooming in summer. and by fall it is covered with lavender to light-blue flowers and butterflies. Keep in mind that this plant can vigorously spread, more so in rich garden soil; so plant it where it has room to roam and don’t pamper it.
Showy goldenrod gets a bad rap every fall, getting blamed for seasonal allergies, when the actual culprit is ragweed, which has inconspicuous blooms. Goldenrod blooms in late summer into fall, showing up in bar ditches, fields and abandoned lots. Many species can be very aggressive spreaders, but there are also varieties that are better behaved and suitable for a sunny spot in your yard. One popular variety is ‘Fireworks’ (Solidago rugosa ‘Fireworks’), which gets topped with abundant sprays of tiny golden-yellow flowers reminiscent of exploding fireworks. Goldenrod is also an excellent pollinator plant for all types of insects.
An amazingly fragrant perennial in the IDEA Garden in Tyler is sweet almond verbena (Aloysia virgata). Even my olfactorily-challenged nose can easily smell the sweet aroma of this tall, dieback perennial. Starting in summer and continuing through fall, it is covered with spikes of aromatic flowers that appeal to swarms of butterflies, bees and other pollinators. This plant always elicits comments from visitors to the garden. It can get very tall every year, so plant it toward the back of your garden bed. Since it blooms on new growth, you can cut it back hard to maintain its height.
These are just a few plants to get you thinking about keeping your yard full of flowers. There are many more fall-blooming perennials to keep your yard beautiful and buzzing with pleasant insects. All the accompanying photos were taken between mid-September and November, and hopefully they inspire you to add some of these plants to make the sometimes-dreary days of fall brighter with blooms.
By Keith Hansen
Smith County Horticulturist, Emeritus
Texas A&M AgriLife Extension Service
Owner, East Texas Gardening