Fern leaf yarrow showy blooms are composed of scores of tiny flowers arranged in a flat cluster. called a corymb.
Fern leaf yarrow is a perennial that has been known to retain its leaves through the winter if it doesn’t get too wintery. This is the tallest and most robust of the yarrows, often getting up to 4 ft (1.2 m) or more in height. Spreading by underground rhizomes, fern leaf yarrow grows in an ever expanding clump that should be divided every 2-3 years. The stout stems bear feathery pinnate leaves with 10-15 pairs of linear segments. The largest leaves (nearer the base of the stems) can be around 10 in (25 cm) long. The foliage is densely hairy and grayish green, but not as grayish as the similar common yarrow (Achillea millefolium). The foliage has a distinctive spicy fragrance. The inflorescence, around 5 in (12 cm) across and larger than common yarrow's, is a flat topped corymb composed of many tiny flowerheads, each with yellow rays and yellow discs.
'Altgold' has corymbs consisting of yellow flowerheads with copper colored edges, and gets only 2 ft (60 cm) tall. 'Gold Plate' has abundant domed flower clusters in rich gold. 'Parker’s Variety' is an especially popular cultivar that is variable and easily grown from seed.
Location Achillea filipendulina hails from Iran and Afghanistan and the Caucasus Mountains in Russia and Georgia. It has become established in parts of Ontario and the northeastern U.S., and in California.
Fern leaf yarrow thrives in poor, sandy, slightly acidic soils. If grown in very fertile soils it may become too lanky and tall and require staking.
Light: Yarrow does best in full sun. Moisture: Yarrow needs a moist but well drained soil. Established plants are fairly resistant to drought, but they can never tolerate heavy, wet soils. Hardiness: USDA Zones 3-9. Yarrows in Zone 3 should get some winter mulch and those in Zone 9 will need some afternoon shade. Many authorities do not include Zone 9 for fern leaf yarrow. Propagation: Divide root clumps, preferably in spring. Plants should be divided every 2-3 years to maintain vigor anyway. Sow seeds where you want the plants to grow and expect flowering in the second year. 'Parker’s Variety' will self seed under optimum conditions.
Fern leaf yarrow's showy flowers and soft ferny foliage make it a favorite for larger beds and borders.
Fern leaf yarrow is a good perennial for borders and informal flower beds. The flowers start blooming in spring and persist through autumn. They are excellent for cutting, whether fresh or dried. Be sure that the flowers are mature (visible pollen) before cutting to get the longest lasting arrangements. Dead heading spent flower clusters will encourage more flowering. Cut the plants back to nearly the ground when flowering has ceased and you may be surprised by a second flush of blooms late in the season.
The yarrows are apparently not in the white-tailed deer’s preferred diet.
The sunflower family includes more than 22,000 currently accepted species, spread across 1620 genera. Only the Orchidaceae has more named species, while the pea family, Fabaceae, comes close. There are about 80 or 90 species in the genus Achillea, but only a half dozen or so are commonly cultivated.
Recall that members of the sunflower (or composite) family, Asteraceae, have inflorescences that are composed of two different kinds of flowers: Ray florets and disc florets. The ray florets look a lot like petals arranged around the perimeter of the flowerhead, whereas the disc florets, concentrated in the center of the head, are small and tubelike. Ray florets may be female or sterile, and disc florets may be bisexual or male. Female and bisexual florets produce the seeds. There are some species in the family that have only disc flowers (e.g., mistflower, Conoclinium coelestinum). The flowers of Achillea have female ray florets and bisexual disc florets.
When the botanists agreed to use a standardized system for naming plant families (all should end in …aceae), there were eight old family names that were so entrenched in the literature that the taxonomists agreed to allow either the newly constructed name or the old name. Thus Asteraceae and Compositae are both correct. The other seven families with two names are: Brassicaceae = Cruciferae; Poaceae = Gramineae; Clusiaceae = Guttiferae; Lamiaceae = Labiatae; Fabaceae = Leguminosae; Arecaceae = Palmae; and Apiaceae = Umbelliferae.
Some people may be sensitive to yarrow foliage and develop a skin rash from contact.