Saturday, September 29, 2007

Asters again

My introduction to asters came about thirty years ago when my mother and I, returning home from the grocery store, slowed down to admire a field of goldenrod. The "field" was a soon to be developed construction site not far from what is now one of the busiest intersections in a very busy part of the county. We stopped to pick some goldenrod, and then saw a spot of purple-blue: it was a robust plant of the New England aster, Aster novae-angliae (aka Symphyotrichum novae-angliae). I came back later and dug the clump. It's hard to say if that plant survives in the garden now: over the years, there have been so many seedlings that it's hard to say which are pieces of the original plant and which are seedlings.

Incidentally, that natural pairing of goldenrod and aster is easily reproduced in the garden. The goldenrod 'Fireworks' makes a particularly good companion.

Other New England aster cultivars have been introduced to the garden, too, and these have crossed with the original plant to produce seedlings in an array of silvery pink, rich pink, dull purple-blue and saturated wine red. The cultivar 'Alma Potschke' provides a color unique among the New England aster cultivars, a vibrant, intense pink-red unlike any other color I know in the genus.

This species is characterized by rough, sometimes clammy, scented foliage. Plants are typically four or five feet high, sometimes more. They begin to bloom in August, although the early flowers are not numerous or conspicuous. They are still blooming in October. Left to grow without attention, they form thick clumps of rigid stems. The counsel of perfection is to divide them annually, spacing each plant about eighteen inches from its neighbor. Don't ask me if I've ever done this.

Other asters growing in the garden include Aster cordifolius (aka Symphyotrichum cordifolium), Aster divaricatus (aka Eurybia divaricata), Aster umbellatus (Doellingeria umbellata) and Aster amellus (aka Aster amellus). The names in parentheses here are old names newly revived to express more clearly the interrelationships of these plants.

Aster cordifolius seeds itself around freely and forms low mounds of smoky blue gray in October.

Aster amellus is one of the European asters, asters which have a variable track record as garden plants in this part of the country. On trial now is the cultivar 'Doktor Otto Petschek'.

One other aster once grew abundantly in this garden but was eventually expelled: the frost aster. This is the small-flowered, weedy aster often seen blooming from cracks in streets or sidewalks, or in rough dry waste places. It's not unusual to see plants blooming even in December, and so it would seem to have value as a late blooming garden plant. But once brought into the garden, it quickly sheds its former poverty and waxes lush and overbearing. When growing well, a single plant can form a four or five foot hemisphere of bloom; and at that late season these plants can be a boon to bees and other nectar foragers. In the border they produce a mist-like lightness of bloom which is very beautiful. After such prolific bloom, the borders will be full of volunteer seedlings the next year and for years thereafter. And the parent plants are rhizomatous, too, and get around freely. Eventually it dawned on me: it's high maintenance and too much of a good thing. Now I enjoy these in the local fields.

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