Asters Late Summer Through Fall

PLANT-TRIAL RESULTS At a glance USDA HARDINESS ZONES: 4 to 8 Awesome CONDITIONS: Full sun to partial shade; moderately fertile, moist, well-drained soil SEASON: Flowers appear from ASTERS late summer through fall. The best ones have strong habits PROpaGATION: Divide in spring, and disease resistance, and they every two to three years. end the season with a bang PESTS: Verticillium wilt, gray mold, powdery mildew, rusts, white smut, aster yellows, and BY RICHARD HAWKE many fungal leaf spots and stem cankers. Also prone to rosy blister gall, aphids, mites, hat would autumn be like with- slugs, snails, and nematodes. out asters? Boring, that’s what. W Thankfully, I live in a place with a plethora of native asters that dot and decorate roadsides, fields, woodlands, and wild spaces. Their ubiquitous nature sometimes saddles them with the reputation of looking too wild, and while you might get your fix of asters from these borrowed landscapes, I wouldn’t want to be without their cheery flowers in my garden, as well. Asters mark the changing seasons in a pageant of colors, blending beautifully with an assortment of grasses and other late- showing perennials. Aster (the Greek word for “star”) is so-named for the starburst effect of its daisylike flowers, but I like to think that its stellar floral show has something to do with it, too. The botanical name of this autumnal star has changed from the simplicity of Aster to tongue twisters such as Doellengeria, Eurybia, and Symphyotrichum— confounding gardeners and professionals alike. Complicating matters a bit, the new names have not been universally embraced; the Royal Horticultural Society, for one, has not yet adopted the changes, but many botanical gardens, native-plant societies, and nurseries have already made the switch. Possibly more important than knowing the Latin name of a given plant is knowing if it is, in fact, a “star” or one of the many asters that, instead, become a disease- infested mess by midseason. ‘Jindai’ Tatarian aster 30 FINE GARDENING | OCTOBER 2015 TOP PERFORMERS that are worth a second look ‘Eastern Star’ white wood aster ‘Kylie’ aster TRIAL PARAMETERS Without flowers, ‘Jindai’ Tatarian aster (Aster tataricus ‘Jindai’, to undulate across the ground, reaching nearly 4 feet wide How many: Since 2003, the Chicago photo, pp. 30–31) might be difficult to peg as an aster. Coarse but only 8 inches tall. ‘Snow Flurry’ makes a superb ground Botanic Garden basal leaves, nearly 2 feet long, look like those of horse radish or cover or edging plant, but it is utter perfection cascading over has evaluated tobacco. Flowering stems begin to grow in midsummer, eventu- the edge of a wall or a container. No description of the diminu- 145 different asters in our com- ally reaching up to 4 feet tall—that’s a tive flowers can do justice to the actual parative trials. good 2 to 3 feet shorter than the spe- show: A veritable snowstorm of white How long: A mini- cies. Come autumn, its lineage is no flowers blanket the stems in autumn. The mum of six years Asters mark the longer in doubt: Clusters of pretty tiny linear leaves are more reminiscent of Zone: 5b violet-blue-and-yellow flowers bloom changing seasons in a heaths (Erica spp. and cvs., Zones 5–11) Conditions: well into late fall and sometimes even than of asters. ‘Snow Flurry’ is also toler- ‘Wartburgstern’ East Indies aster Full sun to full pageant of colors, blending shade; alkaline, early winter. The species has a reputa- beautifully with ant of dry conditions. clay-loam, well- tion for spreading widely, and even drained soil though ‘Jindai’ makes a sizable patch in an assortment of ‘Raydon’s Favorite’ aromatic aster Care: Minimal, allowing plants to a few years, I have not found it to be a grasses and other late- (Symphyotrichum oblongifolium ‘Raydon’s thrive or fail under thug. Bold-textured ‘Jindai’ pairs well Favorite’, right photo, p. 32) was fairly natural conditions with small-leaved asters or any orna- showing perennials. uncommon when we planted it but Observations: mental grass, be it short or tall. quickly became a perennial favorite in our Ornamental traits; growth trial. The plant is loaded with blue-purple and adaptation One of the heartbreaks of our trial was the lack of success in flowers that keep appearing for a long time; in fact, the plant is to environmental and soil condi- overwintering any cultivars of Frikart’s daisy (Aster × frikartii); so eager to get going that precocious blossoms pop up for sev- tions; disease or they all balked at our wet winter soils. Luckily, we found that eral weeks before blooming begins in earnest in midsummer. pest problems; plant injury or ‘Wartburgstern’ East Indies aster (Aster tongolensis ‘Wartburg- A billowy habit gives ‘Raydon’s Favorite’ an informal look that winter losses stern’, top left photo, p. 32) is a hardy substitute. Vibrant, suits it to mass plantings and naturalizing. Aromatic asters are violet-blue flowers with bright orange centers hover 20 inches better alternatives to New England asters (Symphyotrichum above the low mat of dark green leaves, which remain attrac- novae-angliae) because they are more resistant to powdery mil- tive all summer. Although ‘Wartburgstern’ (or ‘Wartburg Star’, dew. I think aromatic aster will play an important role in future as it is often called) is described as blooming all summer, we plant breeding for disease-resistant cultivars and hybrids. saw flowers for only about a month from early to midsummer. Sure, the shorter bloom period was disappointing, but that only ‘Eastern Star’ white wood aster (Eurybia divaricata ‘Eastern made the flowers all the more precious. Star’, photo, top left) is one of the few asters that grows well in shady gardens, although some morning sun enhances its floral The low mounding habit of ‘Snow Flurry’ white heath aster display. From midsummer on, smallish white flowers with yel- (Symphyotrichum ericoides ‘Snow Flurry’, bottom left photo, low centers are borne aplenty on wiry, dark burgundy stems p. 32) sets it apart from other asters. Its arching stems seem over dark green leaves. You can expect an upright mounded ‘Snow Flurry’ white heath aster ‘Raydon’s Favorite’ aromatic aster 32 FINE GARDENING | OCTOBER 2015 FINEGARDENING.COM 33 TOP PERFORMERS that are worth a second look BASICS UP-AND-COMERS to check out ‘Bridal Veil’ aster (Sym- habit, similar to the species, but the cultivar ‘Eastern Star’ fea- Asters, in a nutshell phyotrichum tures larger flowers and darker green leaves. Its arching stems There are roughly 250 species of asters that are native to North ‘Bridal Veil’) has were a bit more recumbent, too, especially when weighed America, Europe, and Asia. Although fairly ubiquitous, they are not its origin at the down with flowers. White wood aster is particularly fetching without their challenges. Chicago Botanic Garden; it was in large drifts in high-shade landscapes. Division keeps selected from a plants healthy cross between It was a friend who told me that ‘Kylie’ aster (Symphyotrichum Fast growers, such as New ‘Snow Flurry’ England aster, New York aster, and an unknown ‘Kylie’, right photo, p. 33), a hybrid of New England aster enner B calico aster, and flat-topped aster. ‘Bridal Veil’ and heath aster, was a must-have for my trial. ‘Kylie’ seems to aster (Doellingeria umbellata), has upward- have gotten the best of both parents, with narrow, dark green benefit from crown division arching stems every few years in early that ultimately leaves—free of rust and mildew—and a robust clumping spring or autumn to rein- turn pendulous, habit. To be honest, the healthy foliage was quickly forgotten vigorate the plants and keep developing a ‘Arrested Development’ aster them shapely. If left alone, the graceful weeping by autumn, when ‘Kylie’ turned into a soft pink cloud with (Aster ‘Arrested Development’) plants will die out in the centers (photo, above). habit as the season progresses. Living up to scores of small semidouble flowers crowding the tops of the is a new introduction noted its name, the fine-textured, cascading stems A new enemy is for its short size. I’ve enjoyed erect stems. Every year, ‘Kylie’ got both the butterfly vote and are thick with ½-inch-diameter white flow- on the loose its deep lavender-blue flow- mine, proving that sometimes it pays to take a friend’s advice. ers from early fall on. At 40 inches tall and Chrysanthemum lace bug ers whenever I can catch it in 68 inches wide, ‘Bridal Veil’ takes up some (Corythucha marmorata), bloom—I have to be one step space, but its organic habit is worth it. Add which became a problem in ahead of the rabbits, though. My first impression of ‘Doktor Otto Petschek’ Italian aster mildew resistance as well as drought and salt our trial in just the past few It touts an early-fall bloom (Aster amellus ‘Doktor Otto Petschek’, photo, top left) as tolerance to the mix and ‘Bridal Veil’ is per- ‘Doktor Otto Petschek’ Italian aster years, sucks nutrients from date, a fact that we observed fect for both urban and naturalistic gardens. just another lavender-flowered aster was way off—as was aster leaves, turning them for the past two years, when the notion that it was named after a Bond villain. Flowers sickly and off-colored (photo, as if on cue, the flowers by the hundreds cloaked this compact clumper for weeks right). Severely infested plants opened on September 18. It is ironic that rabbits kept nib- drop most of their leaves and We all know that fall every fall, looking stunning and remaining healthy when bling at the tips, thus arresting sometimes don’t recover.

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