The yarrow plant (Achillea millefolium) is an herbaceous flowering perennial. Whether you decide to grow yarrow in your flower beds or in your herb garden, it’s still a lovely addition to your yard. Yarrow care is so easy that the plant is virtually care-free. Let’s take a look at how to plant yarrow and also tips for how to grow yarrow.
I. Appearance and Characteristics
Achillea millefolium, commonly known as yarrow or common yarrow, is a flowering plant in the family Asteraceae. The plant is native to temperate regions of the Northern Hemisphere in Asia, Europe, and North America. It has been introduced as a feed for livestock in New Zealand and Australia. Used by some animals, the plant may have somewhat toxic properties, although historically it has been employed for medicinal purposes.
The genus name Achillea is derived from the mythical Greek character Achilles, who reportedly carried it with his army to treat battle wounds. The specific epithet millefolium comes from the featherlike leaves which are minutely divided.
Achillea millefolium is an erect, herbaceous, perennial plant that produces one to several stems 0.2–1 meter (8–40 inches) in height, and has a spreading rhizomatous growth form. Cauline and more or less clasping, the leaves are appear spirally and evenly along the stem, with the largest and most petiolate towards the base; they are 5–20 centimeters (2–8 in) long and fernlike, divided pinnately or tripinnately.
The inflorescence has 4 to 9 phyllaries and contains ray and disk flowers which are white to pink, blooming from March to October. There are generally 3 to 8 ray flowers, which are 3 millimeters (1⁄8 in) long and ovate to round. The tiny disk flowers range from 10 to 40. The inflorescence is produced in a flat-topped capitulum cluster and the inflorescences are visited by many insects, featuring a generalized pollination system. The small achene-like fruits are called cypsela.
The plant has a sweet scent similar to that of chrysanthemums, so powerful that it may be irritating to some.
Yarrow can cause allergic skin rashes. It reportedly can induce menstruation and cause miscarriages.
According to the American Society for the Prevention of Cruelty to Animals, yarrow is toxic to dogs, cats, and horses, causing increased urination, vomiting, diarrhea and dermatitis. When consumed by cows, an unfavorable flavor is given to their milk. In a standard rodent model for reproductive toxicity, aqueous extracts of yarrow produced a significant increase in the percentage of abnormal sperm.
II. How to Grow and Care
Sunlight
Yarrow prefers a garden plot that receives full sunlight, as these conditions will help it stay compact, yielding many blooms. This plant can tolerate partial shade, yet inadequate sunlight may cause it to grow long and spindly, requiring staking.
Temperature and Humidity
Yarrow thrives in warm, summer conditions, with temperatures of 65 F to 75 F, but can start to suffer heat damage if temperatures rise over 86 F. And while generally considered easy-going, yarrow does not like cold drafts or temperatures near freezing. Yarrow can tolerate some humidity, but prefers conditions dry and may fall victim to root rot or fungus if its soil becomes saturated.
Watering
Once established, common yarrow is drought-tolerant. Frequent, light waterings will only be needed to encourage germination and to mature small seedlings. After that, only a 1/2 inch of water weekly is needed to maintain growth. During periods of natural rainfall, cease watering altogether, especially if you’re getting up to, or more than, 1 inch of water per week.
Soil
Common yarrow can adapt to a variety of soil compositions, from sandy, to loamy, to clay. Still, whatever the medium, this plant grows best in dry, well-drained conditions. Avoiding fertilizer or compost is often suggested, as nutrient-rich soil will encourage aggressive, and possibly unwanted, growth.
Fertilizing
Yarrow plants are low-maintenance when it comes to feeding. An annual side-dressing with compost in the spring should be enough to last throughout the season. However, some gardeners choose not to fertilize this plant at all, as nutrient-rich soil may encourage invasive spread.
Pruning
Yarrow needs regular pruning and deadheading in order to keep the plant in a state of continual bloom. Plant stems can grow long in a hot, humid climate, and may require cutting after flowering to reduce plant height and to avoid flopping. Habitual pruning will also help keep the plant in check by preventing self-sowing.
Propagation
In ideal growing conditions, yarrow spreads rapidly and sometimes aggressively. For this reason, it’s best to divide the plant every two to three years, or as needed. Propagating yarrow by division allows you to relocate the same variety to a different area of your garden, or you can gift it to friends looking for additions to their perennial beds.
Here’s how to propagate yarrow through division:
- Gather a spade shovel, gardening gloves, and compost.
- In the spring, just as new growth starts to appear, use your shovel to loosen the soil around the plant.
- Cut the root ball in half with your shovel, and divide one half into the desired number of segments, making sure each one has three, or more, stems attached.
- Add the segments to your garden by digging holes spaced 1 to 2 feet apart and deep enough to accommodate the segment’s root ball.
- Add compost to the hole and mix it into the soil.
- Place the plant in the hole assuring the top of the root ball is flush with the soil line. Backfill the hole with a soil and compost mixture. Water thoroughly.
How to Grow from Seed
Yarrow also proliferates easily from seed sowed in the early spring. In approximately 120 days (three months), your plant will bear breathtaking blooms.
Here’s how to plant yarrow from seed.
- Gather a seedling tray, seed-starting medium, and a heating pad (optional).
- Sow the seeds indoors about eight to 10 weeks before the last predicted frost by distributing them over a tray filled with starting mix. Yarrow needs light to germinate, so sow the seeds on top of the mix—do not cover with soil.
- Press seeds firmly into the mix. Water until moist.
- Place the tray in a warm, sunny window indoors and add a heating pad to the bottom of the tray to help speed germination (optional). In about 10 to 14 days, the seeds will begin to germinate.
- Harden off seedlings by placing the tray outdoors during the day for a week before transplanting them into your garden.
Potting and Repotting
Common yarrow grows tall—some varieties can reach up to 40 inches. To accommodate its growth in containers, you’ll need to use a large pot or choose a dwarf variety. Yarrow grows best in a porous clay or terracotta pot that drains and dries easily. Any standard potting soil will do, but make sure it contains perlite for good drainage.
It’s best to use plant starts when growing yarrow in pots, as you’ll get a jump on maturity and blooming. To do so, fill your pot with potting soil, dig several holes in the soil, and place a start in each one, allowing space in between. Water the pot thoroughly and allow it to drain, and then place it in a sunny patio location. Once established, make sure the soil drys out completely between waterings.
Overwintering
In late autumn, when the temperature starts to drop and your yarrow plant loses its vitality, cut the plant back to its basal leaves. The basal leaves will provide protection for the aboveground parts during the winter, and the act of pruning will allow the plant to focus on its root system during its period of dormancy.
Pests and Diseases
Common Pests & Plant Diseases
Common yarrow may become susceptible to botrytis mold and powdery mildew—both of which will appear as a white powder on the leaves—if its roots are saturated with water. Improving soil conditions and airflow between the plants, as well as plenty of sunshine, can reduce the infection.
Spittlebugs can also move into a patch of yarrow. This infestation will present as specks of “spit” on the plants. If the number of bugs becomes overwhelming, use a strong spray of water from the garden hose to reduce the population and to remove the coating from the bugs. This will expose the bugs to the sun, eventually killing them.
Common Problems
Overwatering is the most common issue with this extremely drought tolerant plant, as roots soaked in water may rot, or fungus may move into the plant. To avoid this, always plant yarrow in well-drained soil and stick to the suggested watering schedule. Avoid watering this plant altogether during periods of rain.
When grown in gardens without direct sun, yarrow stalks may become long and need staking. That said, it is next to impossible to stake a proliferate patch of yarrow. In that instance, all you can do is let it flop to the ground.
III. Uses and Benefits
- Medicinal uses
A. millefolium was used in traditional medicine, in part due to its astringent properties and the mild laxative effect of its leaves. It has been used since ancient times to heal wounds and stop bleeding, and in the sixteenth century the crushed leaves were used to stop nosebleeds. Yarrow and its North American varieties were traditionally used by many Native American nations. The Navajo historically considered it a “life medicine” and chewed the plant for toothaches and used its infusions for earaches. The Miwok in California used the plant as an analgesic and head cold remedy. Native American nations used the plant for healing cuts and abrasions, relief from earaches and throat infections, as well as for an eyewash. Common yarrow was used by Plains indigenous peoples to reduce pain or fever and aid sleep.
In the early 20th century, some Ojibwe people used a decoction of yarrow leaves on hot stones and inhaled it to treat headaches, or applied decoctions of the root onto skin for its stimulating effect.
- Culinary uses
The entire plant is reportedly edible and nutritious, but it is advised not to consume much. The foliage is pungent; both its leaves and flowers are bitter and astringent. The leaves can be eaten young; raw, they can be added to salad. The leaves, with an aniseed-grass flavour, can be brewed as tea.
In the Middle Ages, yarrow was part of a herbal mixture known as gruit used in the flavoring of beer prior to the use of hops. The flowers and leaves are used in making some liquors and bitters.
- Other uses
Yarrow is considered an especially useful companion plant, attracting beneficial insects and repelling some pests. It attracts predatory wasps, which drink the nectar and then use insect pests as food for their larvae. Similarly, it attracts ladybirds and hoverflies.
A. millefolium can be planted to combat soil erosion due to the plant’s resistance to drought. Before the arrival of monocultures of ryegrass, both grass and pasture contained A. millefolium at a density of about 0.3 kg/ha. One factor for its use in grass mixtures was its deep roots, with leaves rich in minerals, minimizing mineral deficiencies in ruminant feed. It was introduced into New Zealand as a drought-tolerant pasture.
Some pick-up sticks are made of yarrow.
Yarrow can be used for dying wool as it contains apigenin and luteolin. Depending on the mordant the color may be green to yellow.
Find Where to Buy the Best Common Yarrow (Achillea millefolium)
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