Wednesday, August 4, 2010

Wildflower Wednesday: Showy Aster

I consider Showy Aster my most successful garden wildflower experiment. The original planting has formed a thick clump about a metre across, a half a metre wide, and 1.2m tall in a shady corridor between a sidewalk and a fence. The tops are covered with good-sized purple-rayed asters with yellow centres from late July. It is a bit floppy in the shade, so requires some support to keep the sidewalk clear, and every now and then a rhizome pops up a shoot in the bed – but they are easily transplanted. The transplants have taken in the front yard in dappled shade and fit right into the woodland theme. The flowers are attractive to butterflies and bees, it does well in both sun and in shade, it is extremely hardy (at least to Zone 2), and it makes a nice link between the Home Bug Garden and the countryside, where it is now a conspicuous adornment. The Edmonton Naturalization Group agrees.
About the only problem with Showy Aster is that it is no longer a ‘star’. Actually, there isn’t much left in the ‘native’ North American Flora that glimmers as a true Aster, except Alpine Aster. Showy Aster, and many others, have been moved to the genus Eurybia and to accommodate the change in generic gender, the male Aster conspicuus (Showy Star) has become the female Eurybia conspicua (Egregious Eurybia?). Since the flowers are hermaphrodites, I don’t suppose they are too impressed with the change. Nor am I, especially since a heap of other former Aster have been moved into the neuter genus Symphyotrichum. So, Lindley’s Aster (attractive when healthy, but unfortunately susceptible to both aphids and mildew) has moved from Aster ciliolatus to Symphyotrichum ciliolatum (and been mostly weeded out of the Home Bug Garden).
In contrast, Smooth Aster, the late Aster laevis, now Symphyotrichum laeve (which the spellchecker keeps changing to ‘leave’) is quite a nice garden plant. It isn’t as showy as Showy Aster, but makes a nice, understated contrast and blooms around the same time. Unfortuantely, Smooth Aster likes the open, lots of sun, and generally drier conditions. So it persists only on the margins of the Home Bug Garden.
 Compared to Symphyotrichum (which probably means ‘grown together hairs’, I would guess in reference to some peculiarity of the pappus), Eurybia is an attractive name. I like to think that Alexandre de Cassini in 1820 used the name in reference to the Eurybia of Greek Mythology – consort of a Titan and a daughter of the Earth and the Sea. Wikipedia, however, speculates that it is from the Greek words for ‘wide’ and ‘few’ and refers to the few and broad ray flowers. Since Showy Aster has numerous narrow ray flowers this seems dubious. In any case, Eurybia is also a genus of metalmark butterflies, and so another Zoo-Bot homonym that should add to the confusion.
The confusion in names doesn’t matter to the butterflies that visit the asters, except perhaps to some. The Pearly Crescent (Phyciodes tharos) is known to feed on ‘asters’ in the obsolete sense, and the Northern Crescent (Phyciodes cocyta) is known to  feed on Symphyotrichum laeve in Colorado. Apparent there is little or no data on what the caterpillars feed on in Alberta, but one or the other of these Crescents (the species are very similar and overlap in range here) was showing quite an interest in Eurybia conspicua this weekend. It would be interesting if the Crescents were discriminating about Eurybia and Symphyotrichum.

1 comment:

  1. Spell-check has made scientific writing so much more difficult!