Sunday, August 02, 2009

Fern-leaf Yarrow

What’s blooming in the area: Tea roses, Apache plume, butterfly bush, trumpet creeper, Japanese honeysuckle, silver lace vine, leather leaved globemallow, bird of paradise, alfalfa, white sweet clover, Russian sage, velvetweed, scarlet beeblossom, white and yellow evening primroses, datura, Heavenly Blue morning glory, creeping and climbing bindweed, buffalo gourd, goats’ head, purple phlox, Queen Anne’s lace, pigweed, cultivated and native sunflower, Hopi tea, goatsbeard, hawkweed, horseweed, wild lettuce, strap and hairy golden aster, plains paper flower tahokia daisy, blue and side oats grama grasses; buds on goldenrod; apples redder.

What’s blooming in my yard, looking north: Hartweg, zucchini, nasturtium, Mexican hat, chocolate flower, blanket flower, black-eyed Susan, chrysanthemum, Parker’s yarrow.

Looking east: Floribunda rose, California and Shirley poppies, hollyhock, winecup, sidalcea, coral bells, bouncing Bess, snapdragons, Jupiter’s beard, coral beardtongue, Maltese cross, pink evening primrose, large-leaved soapwort, cut-leaf coneflower; buds on garlic chives and Maximilian sunflower.

Looking south: Tamarix, Blaze and rugosa roses, rose of Sharon, daylily, bundle flower, sweet pea, zinnia, cosmos.

Looking west: Caryopteris, flax, catmint, lady bells, sea lavender, white spurge, David phlox, perennial four o’clock, purple ice plant, purple coneflower, Mönch aster; buds on leadplant.

Bedding plants: Moss rose, sweet alyssum, tomato.

Inside: South African aptenia.

Animal sightings: Hummingbirds, gecko, bees, large black harvester and small dark ants, grasshoppers.

Weather: Storms that can break a heat wave moved through and left water; 14:53 hours of daylight today.

Weekly update: Whenever you get interested in herbal medicine, the first plant you discover is yarrow. Achillea millefolium leads or terminates any list.

It’s also one of the easiest to find, at least in the Midwest where it blooms in abandoned fields and along the roads in mid-summer. It comes with the nicest stories about Achilles and his troops carrying it with them to staunch bleeding when they were wounded attacking the walls of Troy. Claire Haughton says it spread north with Roman soldiers and east with their Gothic conquerors. Colonists brought it to this country as a band-aid, but it had preceded them across Beringia during the Pleistocene.

Unfortunately, the airy, flat-topped wildflower won’t grow here, and the ornamental varieties sold by nurseries are no substitute. They aren’t white and have little medicinal value.

The flowers of my Achillea filipendulina are more densely packed in clusters composed of clusters of florets topping clusters of stems, branching from more clusters that together form what looks like a round, flat head. The ray flowers are few, appearing at the base of each receptacle and disappearing quickly; the outer disc florets are shorter than the inner ones.

The numerous round disc flowers appear to be empty tubes with only a few, at any time, holding up vital forking organs to relieve the monotony. Everything would be the same, dark gold if individual florets didn’t turn tan as soon as they’d bloom, leaving every honeycombed corymb spotted brown, until nothing is left but moss colored heads.

They’re best seen from a distance, say near the garage or back fence, where large blobs of undifferentiated color are welcome. The Caucasian natives aren’t particularly adapted to gardens. While the green stems are strong enough to hold the heavy heads, they tend to lean, then sag from the weight.

Sweetmagnoliame complained to Gardenweb readers that hers had become such a nuisance she was ready to send them to a neighbor. She had tried plant velcro, then peony supports, but nothing could both stop them from falling in Utah. One of her readers said he’d tried tomato cages, until he just removed the plants.

I have an aversion to getting near mine, either to cut off the darkening heads or counteract the lunging habit because the stems turn rough and irritate my skin. Alan Armitage says when he was testing members of the genus for their potential as open-field cut flowers, his nose ran, his eyes watered, and he sneezed.

You have to wonder, why bother?

Botanists find the genus exciting because many members, especially the common yarrow, have evolved into so many ecotypes they challenge the very concept of species. Breeders have exploited the composites’ ability to interbreed by introducing hybrids like Moonshine derived from clypeolata and taygeata and Coronation Gold descended from filipendulina and clypeolata, although neither combination could thrive in my north facing bed.

A number of new varieties appeared in 1990's, including my Parker’s Variety, when plantsmen were looking for perennials they could produce cheaply from seed. Jelitto tells growers they can have sellable plants 16 weeks after they plant the flattened achenes, and they can be planted anytime. The fern-leaf yarrows look their best soon after the dissected leaves have risen from the rhizomatous crowns, before the stems emerge.

Researchers supporting the cut flower trade have been experimenting with generating plants from small pieces in special mediums to produce disease free plants quickly and cheaply. Filipendulina are particularly interesting because they not only survive for several weeks after they’re cut, but the flowers can even withstand periods without water. Israelis increased their production from 150,000 stems a year to about 1,300,000 with clean stock produced by micropropagation.

Scientific frontiers are exciting to hear about, but they do belong on the frontier of my yard, not in my garden. I’m not going to remove my plants: they justify their armor by blooming reliably, but they won’t be replaced if they ever die. They’ve been there since the year 2000 and show no signs of decline.

Armitage, Alan M. "Yarrows: Aromatic Perennials for Beauty and Variety," in Fine Gardening, Perennials, 1993.

Evenor, Dalia and Moshe Reuveni. "Micropropagation of Achillea filipendulina cv. ‘Parker’," Plant Cell, Tissue and Organ Culture 79:91-93:2004.

Haughton, Claire Shaver. Green Immigrants, 1978.

Jelitto Staudensamen GmbH. "Parker’s Variety," on company website.

Ramsey, Justin. "Rapid Adaptive Divergence in New World Achillea, an Autopolyploid Complex of Ecological Races," Evolution 62:639-653:2008.

Sweetmagnoliame. "Yarrow Gone Amuck," Gardenweb website, 17 June 2007, with response by Digit, 17 June 2007.

Photograph: Parker’s Variety fern-leaf yarrow, rising from Mexican hat leaves, 26 July 2009.

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