This purple flower is a star of autumn in Texas landscapes. Here’s how to care for it
If someone asked you to name the most dramatic color of autumn, odds are the last one on your list would be purple. However, the next time you see a bed of fall asters in full bloom, see if it doesn’t stand out like the headlight of an oncoming train. These babies are gorgeous, and that color just doesn’t come in very many other flowers of the fall. Mums will come close, but there’s something especially dramatic about the regal brilliance of this one.
Tell me, then, how we went so many decades without seeing this plant in garden centers in Texas. You’d see it in older landscapes, and gardeners would share starts with friends, but until the past 25 or 30 years, it was quite difficult, almost impossible, to find this glorious fall star for sale at any garden center in Texas.
Slowly, however, its popularity began to rise. Folks began to pay attention. Botanic gardens started to feature it. All the best butterflies were talking about it. And now, it’s readily available and regularly planted.
If you Google around using the scientific name for this plant (Symphyotrichum oblongifolium — kinda rolls off your tongue, doesn’t it!) you’ll see that it’s native to half of the United States. That even includes wide swaths through Texas, notably the limestone outcroppings in the Hill Country, up through the Metroplex, and clear down to the Rio Grande.
Fall aster is a tough little plant. It grows to 15 to 30 inches tall, but most professional landscape contractors shear it lightly one time in late spring to keep it at the shorter end of those heights and more compact. All you need to do is remove a couple of inches of new growth that one time in late May or early June and you’ll be able to encourage it to produce volumes of side branches. That spells tight mounds of plants and scores more flowers in the display.
The plants have wispy tiny leaves on stems that are equally thin and unnoticeable. They grow steadily without drawing attention to themselves all spring, summer and well into fall before bringing attention to themselves as hundreds of flowers pop open almost overnight in late September or October.
The flowers are rich lavender to purple, and they’re magnets to honeybees and butterflies. They’re perfect companions to fall-blooming mums, marigolds, zinnias, and celosias and brightly colored fall foliage of copper plants, firebush, coleus, Joseph’s coat, and red-leafed celosias.
Fall asters are long-lived perennials. The plants die to the ground soon after they finish blooming. Trim the spent stems back to within 2 or 3 inches of the soil to mark where they’re planted and wait for spring to send them back into action.
If you’re interested in propagating fall asters, that’s done via division in late winter, just before the new growth begins for the spring. Space the transplants 15 to 18 inches apart and fertilize them with a high-nitrogen lawn food applied at half the rate recommended for established perennials as soon as they start to send up new shoots. Water thoroughly immediately after feeding.
Fall asters grow best with full morning sun and light shade from the hot afternoon sun in the summer. They have no serious insect or disease problems, which is probably why you see them at so many neglected or abandoned homesites across Texas. They are tolerant of dry soils, as evidenced by the fact that they’re native to those rocky soils of Central Texas. Even with that, however, fall asters grow and flower best when they’re kept moist all through the growing season.
That’s the story on a lovely plant that’s been waiting patiently for several generations of Texas gardeners to stage its big comeback. It’s not quite there yet, but it’s on its way. Watch at your favorite nurseries this weekend and snatch up a couple. You’ll be back for more as soon as you see it perform.
