How to Grow and Care for a Yarrow Plant
Achillea Millefolium, or Yarrow, is a widely adaptable flowering herb well-suited to hold a lasting place in the perennial sun garden. Native to North America, Yarrow’s popularity has allowed it to find its way into rock gardens and border plantings worldwide.
Not only has the plant spread, but Yarrow lays claim to as many as 85 species. Among those species, varieties come in a range of colors from white to yellow, orange to red, and pink as well.
History of Yarrow
In days of old, yarrow was less a perennial garden favorite, and more of a medicinal must have. It was used in ancient times on the battlefield. Achilles, the Greek hero from whom this herb got its name, is said to have healed his men suffering from battle wounds using yarrow. Used in open wounds, this herb slows the flow of blood
In a place like Greece, I can imagine how yarrow would have covered the hillsides with wide and flat yellow masses of flowers above the silvery gray fernlike foliage. In perfect conditions, yarrow would have spread from seed rather from divisions as we tend to do now.
Starting Yarrow From Seed
Naturally, the flower heads become clusters of seeds that have a period of deep chill through the winter months.
What seeds birds don’t get to are left to go through cold stratification which prepares them for sprouting in the spring.
Seeds purchased from a store may need to be artificially stratified by refrigeration for a period of 4-6 weeks. Once they emerge they will be ready to react to warmth and sunlight.
That sunlight is key when starting yarrow seeds. Sow them thinly and just barely cover with soil so light can penetrate. When kept warm and moist yarrow seeds will sprout in 2-4 weeks. They start very slowly but grow to be very securely established in the fullness of time.
Both spring and fall offer the best chances for directly sown or indoor started yarrow seeds to thrive. If your winters are particularly harsh, forego the fall planting and just hold out for spring. And if you are planning on transplanting from a starter tray into the ground–give your seeds a good 8 to 10 weeks of a head start to get them strong enough for the move.
Prune for Flower Power
You can expect your yarrow to bloom the very first year from seed. Once it begins, it continues to bloom throughout the summer if it is well maintained. Remove spent flowers to keep your yarrow producing those colorful displays for weeks on end.
More Yarrow by Division
As your yarrow matures it will grow new stems around the perimeter of the plant as the center loses its vigor. To keep your plants strong and healthy you can divide each “mother” plant every 2 to 3 years.
Placement in the Yard
Yarrow thrives in full sun in well-drained soil. But even poor soils can support this hardy perennial. Year after year it dies back to the ground and reliably returns in the spring.
Ranging in size from about a foot to two high and equally wide, yarrow becomes decorated with flat broad flower heads that attract all sorts of beneficial garden insects and pollinators to the cutting garden, herb garden, or even in the vegetable patch.
Yarrow’s value increases from ornamental plant to garden support system as thousands of little flowers draw those bees and hoverflies that distribute pollen and ladybugs that devour harmful aphids. Overall, yarrow serves to strengthen the biodiversity in any garden.
Water and Nutrient Needs
Keeping these plants vigorous requires fairly little maintenance. Watering yarrow when there hasn’t been much rain will make sure roots remain healthy in the well-drained soil. Too much watering, however, can lead to that powdery mildew that will ruin the look of your plant. One good soak every week or so is enough for this powerhouse plant.
There’s no need for repeated applications of commercial fertilizer to keep yarrow looking its best. It gets its food through the process of photosynthesis. Even poor soils are enough for this tough guy. However, top dressing with worm compost is a great way to fend off disease and keep yarrow blooming continually.
Once established, yarrow holds its own against harsh summer heat, periods of drought, and most common pests and diseases. When it does become affected by poor conditions such as overcrowding in combination with poor air circulation, yarrow can suffer from powdery mildew, rust, and stem rot. A weakened plant suffers even further from the peach and melon aphids that suck juice from the green parts of the plant.
If you find that you have a diseased or insect-infected yarrow plant, introduce more beneficial ladybugs to your garden and treat the foliage with a vermicompost tea solution. Better yet, pretreat your plants with vermicompost to avoid these issues from the start.
If your plant has been terribly affected, pull the yarrow and discard it so as not to spread the disease to other garden plants.
About AuthorTina Martino Her passion is gardening. Along with her husband and children, each year they grow a garden large enough to provide their family of five with over half of our needed produce. Besides vegetables and a small berry patch, she also focuses her attention on beautifying their home with strategically placed flowers, herbs, and flowering plants. Gardening is more than just a hobby; it is a way of life.