Yarrow, Achillea spp., is a semi-evergreen flowering perennial in the aster, or Asteraceae family.
Suitable for growers in USDA Hardiness Zones 3 to 9, it has corymb, or flattened, flower heads with densely clustered blossoms in shades of pink, red, white, and yellow.
In this article, you’ll learn all you need to know to cultivate and maintain yarrow in your garden.
Here are the topics we’ll explore:
What You’ll Learn
I enjoy growing yarrow in my garden because it offers rich color in return for minimal water and maintenance. I can’t wait to tell you all about it!
Cultivation and History
In ancient Europe and Asia, Achillea was a mainstay of artistic, cosmetic, culinary, medicinal, and even magical applications around the world.
Legend has it that Achilles of Troy used it to treat his wounded soldiers.
There is even evidence to support its use in burial rituals as far back as the time of the Neanderthals, with fossilized pollen found at the Shanidar burial site in Iraq.
Fast forward to the US today, where common yarrow, A. millefolium, as well as modern cultivars and hybrids, are still used in cooking, fresh and dry floral design, and herbal remedies.
There are nearly 100 species in the genus Achillea. They are best suited to USDA Hardiness Zones 3 to 9, although you may have success growing them as far north as Zone 2, and as far south as Zone 10.
According to Wanda MacLachlan et al, at the Cooperative Extension Service of the University of Maryland, A. clypeolata, A. filipendulina, A. millefolium, A. ptarmica, and A. taygetea have been hybridized to create the majority of today’s cultivars.
They are especially prized by the cut flower industry for their large blooms, sturdy stems, and wide array of colors.
For the home garden, you are most likely to find cultivars of A. millefolium and A. filipendulina.
A. millefolium, common yarrow, aka milfoil, is a species with two- to three-inch white flower heads, and mature heights of up to three feet.
It spreads so vigorously that it may become invasive in some regions. Contact your local agricultural extension before planting it, to determine its likely behavior in your area.
You can learn more about the benefits and uses of yarrow in this article.
A. filipendulina, aka fern leaf yarrow, is also commonly called milfoil. The botanical species, as found in the wild, has four-inch mustard yellow flower heads.
Cultivars are yellow of varying hues, with flowers of up to six inches across, and heights up to four feet.
The erect stems of the various Achillea species are noteworthy for being stiff and strong. The foliage is soft, and ranges from medium green to silver-green, with light fuzz. It is deeply serrated and feathery.
A Note of Caution
Please note that Achillea may cause allergic reactions in people with sensitivity to members of the Asteraceae family of plants. In addition, it is toxic to cats, dogs, and horses.
To grow this colorful perennial, you can sow seeds, divide existing plants, or take tip cuttings.
The experts at the University of Maryland’s Cooperative Extension Service offer excellent growing guidance.
Let’s consider the three methods per their recommendations.
Germination takes one to two weeks. Ideal conditions include a temperature of 65-70°F and 90% humidity.
Once sprouted, the temperature may be reduced to 55-60°F.
You can thin the seedlings and transplant the sturdiest plants to individual pots at this time, and fertilize with a high nitrogen fertilizer according to the package instructions.
Alternatively, you may direct sow seeds in the garden at a depth of 1/2 inch, after the last average frost date for your region has passed.
Apply high nitrogen fertilizer once, just after the seeds sprout. Expect flowers in the second year.
You can make new plants by dividing mature ones in early spring. The advantage of this method is that divisions will replicate the exact traits of the parent plant.
Choose a section of plant with 2-3 stems and cut straight down through the thick rhizomes to separate it from the main clump, for immediate planting elsewhere.
For more information about how to do this, check out our guide to dividing perennials.
From Tip Cuttings
To propagate cuttings, take a sharp knife and cleanly cut a stem of soft spring growth off at the third or fourth leaf node down from the top, about 6 inches long.
Remove the lower two leaves to reveal a bare stem.
Place the stem into potting medium, such as a mixture of vermiculite or perlite and peat moss.
Place in a greenhouse or other sunny location with low humidity and temperatures of approximately 50-60°F.
Once new growth is evident, plants have rooted and are ready for transplanting to the garden.
How to Grow
Yarrow is a hardy, cold- and drought-tolerant perennial that blooms from June to September. Its stiff, flattened flower heads are made up of multiple tiny blossoms, some with contrasting centers.
To cultivate it, choose a full sun location.
The ideal soil is sandy, and of average to poor quality. This is one plant that does not have a preference for organically-rich loam.
It can grow in fertile soil, but will likely grow too fast and become “leggy,” and which can result in the stems flopping under the weight of heavy blooms.
The soil pH should be between 4.0 and 8.0. A measurement of 6.4 is considered optimal. To determine your soil’s pH, conduct a soil test through your local agricultural extension office.
The soil quality may be somewhat poor, but the drainage must be excellent. Yarrow is not a plant that puts up with wet feet, nor humid conditions.
Achillea thrives best in dry heat. However, there are cultivated hybrid series such as Galaxy and Seduction that tolerate some humidity.
Plants average two to four feet tall at maturity, although some botanical species (as found in the wild) may be shorter, and there are hybrids that may top out at a towering five feet.
Widths range from one to three feet.
Be sure to account for mature dimensions when choosing your planting location. Achillea species are vigorous growers, and reach mature dimensions in the second year of growth.
Whether you start with seeds, divisions, or tip cuttings, new plants require about an inch of water per week to help them to establish strong, deep roots. If it rains an inch, you can skip the additional irrigation.
Once established, yarrow is a water-wise, drought-resistant powerhouse. However, if a dry spell is prolonged, please water it, rather than test its tolerance.
Once established, a sturdy plant like yarrow works hard in the garden, especially when you remember these three tips for success:
- Choose humidity-tolerant cultivars if needed.
- Poor soil is better than rich to promote compact plants that grow at a moderate rate.
- Drought tolerance doesn’t mean you should never water.
Give your plants a good start and they’ll reward you with years of color, in exchange for a little upkeep. Let’s find out just how little is required.
Pruning and Maintenance
If you establish your plants with care, and it rains every once in a while, you may be able to get through an entire summer without providing supplemental water.
However, in the prolonged absence of rain, you may want to drag the hose out, especially with first-year plants.
When you grow Achillea, you’ll become familiar with its habits. There are generally two main flushes of bloom; one is in spring, and the other is later in the summer.
You may prune plants deeply, by about one-half, after the first flush of flowers, to keep the overall shape compact and encourage further blooming.
You may also deadhead, or remove each spent flower stalk as it finishes, to prevent self-sowing, encourage more blooms, and keep plants tidy.
In addition, at season’s end, you can leave the dead flower stalks attached and let them drop their seed, cut them for dried arrangements, or prune them to the ground.
I like to deadhead during the summer, and leave the last blooms on for winter interest and wildlife habitat. Plants will die back and go dormant over the winter months.
If you choose to leave the stalks attached, you may rake everything up in late winter or early spring, before the new shoots appear.
Please note: seed dropped by yarrow may or may not replicate the traits of the parent plant from which it fell. Only true botanical species produce true seeds. Hybrids of two or more species may produce plants with characteristics of the various component species, but not of the hybrid they formed.
The yarrow you grow is likely to naturalize, forming an intricate system of rhizomes.
Every three years or so, it’s a good idea to divide your plants to rejuvenate them and increase airflow. You can plant the divisions elsewhere in the garden or give them to your friends.
The best time for dividing, or moving entire plants, is in late winter or early spring when new shoots first appear, but before the growing season is in full force.
Tall varieties and those planted in soil that’s too fertile may require staking to provide stability.
Cultivars to Select
With a handle on the ins and outs of yarrow cultivation, it’s time to check out some of the vivid hues available.
Below are three of my favorite cultivars, and you can learn more about the different varieties of yarrow here.
A. millefolium ‘Cerise Queen’ is a common yarrow cultivar. Flowers are deep pink with white centers. It is appreciated for retaining its rich color when others pale in summer heat.
Stems grow to a modest 2 feet tall, and form a compact plant with basal mounds of feathery, medium-green foliage.
Find ‘Cerise Queen’ seeds now from Eden Brothers in one ounce or 1/4 -pound packages.
A. filipendulina ‘Gold Plate’ is a fern leaf cultivar with the distinctive mustard-yellow flowers of the species.
However, this cultivar is an enhanced version of the wildflower and it boasts exceptionally large, 6-inch flower heads.
Equally impressive are its 4- to 5-foot stems that rise from mounds of fern-like silvery green basal leaves.
Find seeds in a variety of packet sizes from True Leaf Market.
A. millefolium ‘Paprika’ is a brick red cultivar of common yarrow with contrasting gold centers. It fades gracefully to shades of pink and cream in the summer garden.
This is a Galaxy Series selection that is suitable for more humid climates.
The flowers of this variety are medium-sized and measure 2 to 3 inches across.
Mounds of medium-green, feathery basal foliage surround stems that top out at 2 feet tall.
Find ‘Paprika’ plants now from Nature Hills Nursery in #1 containers.
Whatever colors and heights you choose, the smooth, velvety flower heads of yarrow are sure to stand out in the summer garden.
Managing Pests and Disease
Yarrow isn’t particularly susceptible to pest and disease issues.
Plants that are healthy are the least likely to have problems. Those that are stressed by less than optimal conditions may become vulnerable to infestation and infection.
If you’ve planted in soil that is fertile, with an excess of moisture or a lack of airflow, you are extending an open invitation to pests and disease.
Pests to watch out for include:
If a spray from the hose nozzle doesn’t wash them away, these pests may be addressed with an insecticidal soap or neem oil.
Damage to leaves, stems, and roots may require removal of affected plants and a fallow period to inhibit the spread of infection, particularly when it is soil-borne.
Fungal conditions may respond to treatment with fungicides.
If your plants show signs of deformity, discoloration, stunting, or wilting, contact your local agricultural extension to discuss specifics and make determinations.
Diseases to be aware of include:
Also known as gray mold, botrytis blight is a fungal infection caused by various species in the Botrytis genus. Symptoms include brown, dead areas on the stems, flowers, and foliage. It’s most likely to occur in damp conditions.
Another fungal infection, leaf spot results in brown spots appearing on the foliage and is caused by a number of different species in the Septoria or Alternaria genera. Damp conditions and lack of airflow between plants contributes to this condition.
A common fungal infection, powdery mildew appears as a white powdery substance on the foliage of your plants. Treat with neem oil or in the case of bad infections, a fungicide.
Caused by soil-borne fungi Rhizoctonia solani or Pythium spp., root rot is does not respond well to fungicide treatments. Plants will fail to thrive, and roots and stems appear black or brown. Remove and dispose of infected plants.
Rust colored spores on stems and leaves appear, caused by the fungus Puccinia cnini-oleracei. Surrounding tissue can turn brown and in the case of a bad infection, growth can be stunted.
You can’t ask for a more cooperative garden flower than yarrow. Once established, it requires little water and asks only that you deadhead regularly to promote prolific blooming.
An attractive and reliable choice for beds, butterfly gardens, containers, and mixed borders, Achillea species and cultivars earn their keep in important ways.
They also repel herbivores like deer and rabbits with their pungent odor and taste.
In addition, their root systems run deep and pull up essential nutrients like calcium, copper, magnesium, phosphorus, and potassium that are advantageous to neighboring plants, like herbs and vegetables.
Use low growing varieties of yarrow in place of grass as a ground cover, or in sunny meadows.
Add it to low-water, low-maintenance xeriscapes, where it plays well with other sandy-soil lovers like bee balm, calamint, catmint, coneflower, eryngium, globe amaranth, lavender, sage, salvia, and small globe thistle.
For seashore gardening, it can’t be beat for salt and wind tolerance.
And if you love to bring flowers inside like I do, you’ll appreciate the sturdiness of both fresh and dry yarrow stems and flower heads in vase arrangements.
Quick Reference Growing Guide
It Doesn’t Get Any Easier
I know you have a spot in the yard with poor soil and lots of sun, where you haven’t been able to get much of anything to grow. We all do.
Give yarrow a try. When it likes a location, it digs in and gets better each year. You’re going to love the colors and the way the flat tops look like velvet tapestry.
I have often shopped for yarrow at the end of summer, and picked up post-bloom-cheap plants. I’ve bought rootbound pots in potluck colors and heights, and I’ve never been disappointed.
I just pop them into the ground as soon as I get home, and forget about them until they burst into bloom the following summer.
Anything that can thrive on neglect and produce stunning flowers deserves a place in the garden planner, don’t you think?
If you’re interested in growing more attractive flowers used as both culinary and medicinal herbs, you may enjoy the following:
- A Medicinal and Visual Delight: How to Grow Feverfew
- Grow Evening Primrose for Late-Day Beauty
- How to Grow Fenugreek
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About Nan Schiller
Nan Schiller is a writer with deep roots in the soil of southeastern Pennsylvania. Her background includes landscape and floral design, a BS in business from Villanova University, and a Certificate of Merit in floral design from Longwood Gardens. An advocate of organic gardening with native plants, she’s always got dirt under her nails and freckles on her nose. With wit and hopefully some wisdom, she shares what she’s learned and is always ready to dig into a new project!