By Natalie Brewer, University of Md Extension Master Gardener
The goddess Virgo cried. And where her tears fell to the earth, asters sprang up from the ground.
My favorite season is autumn. The weather is cooler, the sun shines abundantly, and I love the autumn colors of red, yellow and orange… and blue, purple and pink. Yes, that’s right, blue, purple and pink, and you can add to that magenta, rose, red-purple, royal blue, lavender and sky blue. These are all the true colors of autumn here in the United States due to one of our most glorious and prolific wildflowers, the aster.
Asters are heralds of the autumn garden. There are nearly one hundred and fifty different species of native asters in the United States, many of which (over 50) are native east of the Mississippi River. There are so many different asters with many different qualities that there is definitely an aster for the likes of every gardener and every gardening situation. Asters are beautiful, easy to grow, and blanket themselves in a flush of bloom.
My all-time favorite flowers are the asters that bloom in fall. They bloom so late in the season, that Henry David Thoreau wrote in his diary that just when it seemed that Nature herself had finished all of her work and was done for the season, the asters started blooming. I love the combination of the warm reds, yellows and oranges from our native trees and grasses, combined with the contrasting bright blues, purples and pinks of asters. It is simply stunning, and only Mother Nature herself could have dared to compose something so spectacular.
The word aster literally means ‘star’. There is much folklore attached to the name of the aster, from aster flowers springing up from Virgo’s fretful tears, to someone stealing stars in the night sky and planting them in the fields. The stories are descriptive and indicate the love-affair that people have had with asters throughout history.
Originally, asters were named asters because of their star-like appearance. However, in 1994, due to some DNA testing, many asters were further divided into other families and no longer carry the botanical name of aster, but instead have names such as Eurybia and Symphyotrichum. Not nearly the romantic image that the Greek word, aster, or star implies, but nonetheless, more scientifically correct.
[Editor’s Note: At Behnke’s, we are still desperately clinging to the old names in this case, so we are still using “Aster” on our labeling and signage.]
People are not the only ones who find asters irresistible. All asters are important to wildlife. Wild asters provide an important source of nectar late in the season when many butterflies are stressed while preparing for the winter. Depending on the butterfly, preparation for winter means either forming a chrysalis, laying eggs, migrating, or hibernating, all of which require copious amounts of extra nutrition and calories. Every aster “flower” is actually composed of numerous tiny flowers compacted into a small area which give lots of nectar within a small amount of space.
A significant yield of food in close proximity means good nutrition without a lot of exertion, an important thing to consider when preparing for the approaching season of hardship. In addition, if you do not cut back the flower heads and let them stay in your garden throughout the winter, cardinals, goldfinches, sparrows, chickadees, and towhees are sure to come for the seeds. In fact, more than 30 species of birds incorporate aster seeds into their diets.
[Editor’s Note: that said, the seeds beget new asters, and leaving the seed will result in additional weeding in formal gardens.]
Because of their popularity, there are many eye-catching fall-blooming asters that are readily available in the nursery trade. Many early botanists thought that asters were the most valuable garden plants of all other natives, and by the amount of different cultivars available, it is easy to come to the conclusion that asters are still considered to be valuable plants by gardeners today. There are many asters that are worth trying out in your garden this fall.
New England aster has many cultivated varieties that offer different colored blooms and a variety of statures. It is hardly an autumn garden without at least a few varieties of New England aster planted throughout. The native species, Symphyotrichum novae-angliae, is a gorgeous native which is also a valuable plant to wildlife and is the host plant to the charming Pearl Crescent butterfly.
New England aster boasts bright purple-hued flowers on a plant that can grow to be more than three feet tall. Cultivated varieties include ‘Alma Potschke’ (Symphyotrichum novae-angliae ‘Alma Potschke’) with sumptuous rose-pink flowers, and ‘Purple Dome’ (S. novae-angliae ‘ Purple Dome’) a smaller plant with luscious purple flowers. Try these asters with switchgrass.
A nice combination would be ‘Alma Potschke’ with ‘Shenandoah’ switchgrass (Panicum virgatum ‘Shenandoah’) whose rose-colored flowers will offset the maroon foliage of the grass. ‘Purple Dome’ would look nice with ‘Dallas Blues’ (P. virgatum ‘Dallas Blues’) and play off the purple flowers of the aster with the steel blue foliage of the switchgrass. Or you can use any combination for a stunning effect that is low-maintenance and beautiful.
Aromatic aster is a lesser known aster but is nonetheless a stunning flower. ‘Raydon’s Favorite’ (Symphyotrichum oblongifolius ‘Raydon’s Favorite’), is an opulent medium blue aster that grows to about 30” tall. ‘October Skies’ (S. oblongifolius ‘October Skies’) is a darker sky blue flower that only grows to about 20” tall. Plant these asters with yellow flowers, such as goldenrod ‘Fireworks’ (Solidago rugosa ‘Fireworks’) and you’ll have a display that will rival any Fourth of July fireworks show.
New York aster is another all-time favorite for gardeners. Many cultivars are also available. Here are a few to try. ‘Professor Anton Kippenberg’ (S. novi-belgii ‘Professor Anton Kippenberg’) is a dwarf cultivar growing to about 15” tall with clear lavender-blue semi-double flowers. Plant this among clumps of purple love grass (Eragrostis spectabilis) or little bluestem (Schizachyrium scoparium) for a play on color, form and texture.
For something a little taller, try ‘Winston Churchill’ (S. novi-belgii ‘Winston Churchill’), which boasts vivid pink flowers reminiscent of the color of lipstick popular in the fifties. ‘Winston Churchill’ grows to a height of about three feet. Combine ‘Winston Churchill’ with goldenrods, black-eyed Susans, and big bluestem grasses (Andropogon gerardii) for a sizzling end-of-season display.
All of the asters above have sunny yellow centers, like tiny replicas of the sun. The combination of the brightly colored flowers, with a disc of sunny yellow in the center, is captivating in and of itself. However, take it up a notch by bringing out the golden centers of asters and planting them with something yellow such as goldenrods, black-eyed Susans, or dainty Maryland goldenasters (Chrysopsis mariana). Asters and native ornamental grasses are not only a timeless combination, but also, a vital food source combination that seed eating birds have evolved with for many centuries.
Note that some of the taller asters can become a little leggy and the bottom leaves can become a little dry before the end of the season. I recommend planting something in front of asters in order to hide the bottom half of the stems. This should be easy, since many of the asters are more than two feet tall. On shorter asters, the heavy blooming generally hides any foliar “defects.”
The most commonly grown asters almost always get two fungal diseases—powdery mildew, which cover the leaves in a powdery growth, and rust, which starts as orange spots on the leaves and end with the leaf browning and dropping. Neither seems to do serious damage to the plant, but these are the cause of the tired looking foliage mentioned above.
All of these asters will grow well in full sun with average to moist, well-drained soil. In addition, asters make for a lovely cut-flower arrangement, so don’t forget to plant enough so that you can enjoy them in the house as well as in the garden.
I guess it was a good thing for wildlife and for all of us gardeners, all those years ago, when Virgo shed her tears. All I get is a face full of runny mascara.
Photos by Larry Hurley.