A Weed to Love : Yarrow may be the latest pretender to the turf throne
“My dad doesn’t worry about weeding his lawn,” said San Diego environmental designer Anita bi’Yazi, “It is weeds.”
Indeed it is, but it is one weed in particular, an ancient herb named yarrow, and it was planted on purpose. Most books on lawns and turf grasses consider yarrow a weed, a tough and invasive one at that, but this toughness is what suggested that it might make a serviceable substitute for a blade grass lawn. Although it is still too early to tell, yarrow may be the latest pretender to the turf throne.
Bi’Yazi’s yarrow lawn is now 3 years old--a soft ferny-looking meadow of bright green. It needs little water and infrequent mowing, yet stands up to foot traffic and canine rough housing. Though this is not the first such use of yarrow, it is perhaps the first use in a typical suburban front yard.
Bob Perry, in the Department of Landscape Architecture at Cal Poly Pomona, planted a yarrow meadow at the historic Lummis House, operated by the Southern California Historical Society in the Arroyo Seco, just off the Pasadena Freeway. This yarrow lawn can be visited any week, Friday through Sunday from 12 to 4 p.m., if you want to see one firsthand.
At various times, hundreds have trampled across it (as many as 2,000 during an annual April event), yet after almost five years, it remains green and lush.
Perry pointed out that there are some thin areas in the meadow, even a few bare spots, and that he still thinks turf grasses make a tighter, denser cover that can stand more play or traffic, but he’s convinced there is a place for yarrow in front or back yards where a more natural, water-thrifty turf is called for.
Perry got the idea from Randall Ismay of Water and Landscape Management Consultants in Laguna Niguel, who has been using yarrows in hydroseeding mixes to stabilize slopes. They noticed that it looked quite good when it invaded turf-grass areas that were being mowed and decided to give it a try as a lawn. Ismay did several test plots at Mission Viejo (some are now 12 years old) and Perry planted the Lummis meadow.
The Lummis lawn is only mowed when one of the volunteer gardeners brings a mower, about four or five times a year. Anita bi’Yazi’s dad mows his yarrow lawn every three to four months, which gives it enough time to get bushy and flower between shearings.
Yarrows have distinctive flat-topped flower heads and they have been grown as perennials in garden beds for a long time. Until recently, the best known were the tall, bright-yellow kinds. In the last few years, new shorter kinds with paprika and cerise-colored flowers have become popular in drought-resistant designs.
The deep-rooted, drought-resistant yarrows spread by underground rhizomes, quickly colonizing ground. The kind being used as a lawn, the common Achillea millefolium , has plain, white flowers and grows only a few inches high, although the flower stalks are 12 to 18 inches tall. It does not seem to spread into flower beds, though in both gardens mulches protect the shrubs and flowers around the lawn.
Bi’Yazi sets the mower on its highest setting, so it cuts the yarrow at about 1 1/2 inches. She rakes up the clippings and uses them in the compost pile. Yarrow is an almost mystical compost ingredient, praised by bio-dynamic gardening guru Rudolph Steiner.
Randall Ismay cautioned that mowing high may make a prettier lawn but that the base of the plants will become woody in time. At that point, he suggests mowing as low as the mower will go, and then reseeding to give the yarrow a fresh start, which is probably a good idea every few years anyway, as it is with grass lawns.
If you get tired of mowing, said Ismay, “you can just walk away from it and have a meadow of wildflowers.”
Yarrows are drought resistant but they can’t do without water completely. In the bi’Yazi garden, they are watered with the old lawn’s sprinklers, for about 10 minutes every week. Her yarrow lawn grows in a typically heavy clay soil.
At the Lummis House, the meadow gets watered twice a week in summer for a total of 20 minutes every week, but the soil there is very sandy and dries out quickly. Six-inch tall pop-up sprinklers deliver the water.
Twice a year, volunteers take out any weeds, including grasses, that may have invaded, but there are few weeds to pull.
Bi’Yazi has no weeds or worn areas, even though her two dogs, small Chihuahuas, regularly romp and roll on the yarrow.
She also points to a parking strip in front of her neighbor’s house, planted to yarrow.
It gets even more traffic, but less water, stays close to the ground and is quite dense. Those narrow little strips between sidewalk and street may be the perfect place for a yarrow meadow. They certainly would be the place to experiment.
Bi’Yazi began her lawn from a mix of seed and young nursery plants; the Lummis lawn was started from seed. Seeds sprout in about a week if kept constantly moist. They need not be covered, simply scattered over the prepared soil.
Two sources for seed are Moon Mountain Wildflowers, P.O. Box 34, Morro Bay, CA 93443 and Wildseed Farms, 1101 Campo Rosa Road, P.O. Box 308, Eagle Lake, TX 77434. Both sell Achillea millefolium seed by the pound and Randall Ismay says it takes 15 to 20 pounds of seed to cover 1,000 square feet (when it comes time to renovate and reseed, he suggests using 10 pounds per 1,000 square feet).
There may be one other plus for yarrow over grass. Bi’Yazi swears that her dogs no longer have fleas because of the yarrow lawn, attributing it to the herb’s oil content (an oil called sesquiterpene) and the drier soil surface.