STATEN ISLAND, N.Y. -- Yarrow, botanically known as Achillea, is an herbaceous perennial belonging to the Aster family, known for its medicinal properties. The name Achillea is derived from the Greek god, Achilles, known for his expertise with medicinal herbs.
Some of the more than 85 species of yarrow were popular as medicinal herbs. The common yarrow is known as a healing herb. Its leaves have been used topically for healing wounds such as cuts and abrasions. Additionally, it has been known to help in coagulating blood and relieving symptoms of toothaches, fevers, bronchitis, colds and headaches.
Yarrow is considered to have many useful qualities in the garden as well. Known to repel harmful insects, while attracting good insects, it will improve the soil surrounding it. Yarrow also is believed to have a beneficial effect on its companions when placed near plants that are not in good health.
Generally reaching about 3 feet in height, Achillea has 3- to 6-inch showy, flattened flowers consisting of small, tightly packed flower heads. The fragrant, feathery foliage produces a scent similar to chrysanthemums. This old-fashioned perennial with delicate foliage, blooms beginning in June and continues throughout the summer months.
Garden varieties generally have been hybridized from several species including Achillea millefolium and Achillea filipendulina. The common yarrow, Achillea millefolium, may become leggy when grown in very wet conditions or during early bouts of hot weather. Cutting back by one-third to one-half right after the first blooming period will help to prevent flopping. Further shearing, down to the basal foliage, after the second bloom is finished also will help.
Cutting back plants by one-half or two-thirds in June when they are about 18 inches tall and before any flowering has begun will produce stocky plants that won’t flop over.
The new German hybrid, Achillea millefolium “Paprika,” with its striking large, ruby-red and salmon flowers with yellow eyes, is a magnet for butterflies. Achillea millefolium “Pomegranate” is a compact and bushy plant whose stems don’t tend to flop as much as many of the taller millefolium cultivars.
Cultivars of Achillea filipendulina tend to be a bit taller, with larger flowers than Achillea millefolium varieties. Royal Horticulural Society Award of Garden Merit winner Achillea filipendulina “Moonshine,” with its 4-inch, pale lemon-yellow flowers, is one of the most spectacular varieties.
As the flowers fade, you’ll need to deadhead to lateral or side buds, to encourage further bloom. When the lateral flowers have finished, cut down the plant to the lower basal foliage.
Another award-winner is Achillea filipendulina “Coronation Gold,” one of the best yarrows for hot and humid summers. This cultivar, which produces golden yellow flowers, was named in honor of Queen Elizabeth’s coronation in 1953. It is still considered one of the best yarrows.
Another of the filipendulina cultivars is “Oertel’s Rose,” which sports a variety of colors ranging from vibrant pink to rose-pink, until finally turning a pastel pink. Also look for the newcomer Achillea “Pink Grapefruit,” noted for its compact growth and large deep rose-pink flowers that fade to a pale creamy rose color.
Once established in the garden, yarrow will thrive for years with very little maintenance. It will do well if planted in the middle or back of a border, in a rock garden or in combination with bold textured plants. This sun-lover enjoys well-drained soil that is not overly rich in nutrients. While fertilizing tends to encourage growth to the point of making it necessary to stake them, once established, yarrow plants can tolerate periods of drought.
Yarrow, frequently planted in butterfly gardens, is an excellent plant for both cutting and drying. Make sure to pick them before they start to turn a brownish color. Deadheading fading blossoms and severely cutting back foliage will extend the bloom period. An interesting feature is that masses of yarrow flowers often are found in a variety of subtle shades of color depending on their bloom maturity.
It’s a good idea to divide your Achillea after three or four years to keep the rhizomes from spreading and to promote good air circulation. A good time to divide yarrow is in either early fall or spring.
Yarrow easily can be propagated by seeds. Since they need light to sprout, they should be planted no deeper than ¼ inch. Germination should take about 12 days when the temperature is about 70 degrees. You can expect to see flowers the following year.
Beneficial insects are the natural control for many garden pests. Include plants in the Aster family, such as yarrow; the Carrot family including Queen Anne’s lace, coneflowers, coreopsis and goldenrod, and the Mustard family with basket-of-gold and sweet alyssum for good biological pest control in your garden.
Lee Gugliada is past president of the Great Kills Garden Club and past director of First District Federated Garden Clubs of New York State.