Yarrow
Yarrow, or Achillea millefolium, is a perennial flowering plant grown both for its attractive Daisy-like flowers and for its herbaceous foliage. It is native to cold and temperate parts of the Northern Hemisphere, often growing in grassy meadows and open woodlands. The flowers vary in color and typically bloom in summer and early fall. Yarrow has a long history of medicinal use and has attractive, aromatic foliage when crushed.
Yarrow prefers well-drained soil and should be watered regularly, with 1-2 inches of water per week. During the warmer months, target a soil moisture level of approximately 50% – log in little more in periods of drought. Overwatering can lead to root rot, so make sure to allow the soil to dry out completely between waterings.
Yarrow is known to be suitable for full sun or partial shade, with just a few hours of sunlight or bright indoor light each day preferred. When grown outdoors, Yarrow can tolerate some shade or full sun, although it usually flowers better in full sun. If grown indoors, make sure to keep the leaves out of direct sunlight to prevent sunburns.
Yarrow likes cooler temperatures and does best in temperatures ranging from 34–77°F (1-25°C). During the summer months, temperatures should not exceed 77°F (25°C). In the winter, temperatures should not stay below 41°F (5°C).
This plant likes moderate to high levels of humidity, so make sure to regularly mist it in drier climates or provide a humidifier to increase the moisture level around the plant. This will prevent the foliage from drying out and becoming brittle.
Yarrow likes soil that is slightly acidic (pH 6.5–7.5). It should be high in organic matter, loose and well-aerated. When planting in containers, use a good quality, all-purpose potting mix. If planting in-ground, make sure to loosen or amend the soil to ensure good drainage and aeration.
Yarrow responds well to regular fertilization, particularly in the late winter or early spring. Choose a balanced fertilizer with an NPK ratio of 10-10-10 and use it according to the manufacturer’s directions. Make sure to water the plant well after fertilizing, to ensure even distribution throughout the soil. Too much fertilizer can burn or damage the plant, so take care not to over fertilize.
Yarrow is resistant to most common pests, although it can be affected by scales, spider mites, aphids and whiteflies. If these pests are noticed, use natural insecticides or horticultural sprays to fight them off. Make sure to regularly inspect the plant and remove any affected parts with scissors or a sharp knife to keep them from spreading.
Yarrow can be repotted every two to three years, in early spring or fall. This is typically done to provide the plant with more space to grow, as well as to refresh the soil. When repotting, use a high quality potting mix that is slightly acidic and provide it with plenty of drainage.
Yarrow can be pruned to maintain a desired shape, as well as to encourage new growth. When pruning, use sharp shears, and make sure to cut above a leaf node to prevent the plant from being leggy or overly woody. When trimming off dead or diseased parts, make sure to sterilize the scissors between cuts.
Yarrow can benefit from a layer of organic mulch, such as wood chips or leaf litter. This will help keep the soil moist and protected from extreme temperatures. Mulch should be kept away from the stem or trunk of the plant and replenished regularly.
Yarrow can be propagated either from seed or from stem cuttings. When propagating from stem cuttings, remove a few, 2–4” long sections from a parent plant, dip the cut end in rooting hormone and plant in moist, well-draining soil. Make sure to keep the soil moist and provide plenty of warm, bright light to encourage root formation.
Yarrow can grow quite tall, so it is important to provide it with support, either a stake or a bamboo cage. This will help keep the plant upright and allow it to grow to its full potential.
Yarrow is known to be a fast-growing plant, so it may require a rest period in the winter. During this time, the plant goes dormant and stops producing foliage and flowers. The rest period is typically triggered by shorter days and colder temperatures. During this time, reduce water and move the plant to a cooler location.
Yes, yarrow is toxic to cats and dogs if ingested, so it should not be grown in homes where these pets are present.