The joy of summer green and beauty of cool white are accurate descriptors of the Yarrow, Achillea millefolium, in my garden. Gifted to me as a passalong plant some 20 odd years ago, it is a plant that is lovely to view and easy to grow.
A member of the Asteraceae (Aster) family, common Yarrow grows throughout a large area of continental North America. According to the Lady Bird Johnson Wildflower Center (LBJWC) plant data base, the plant is classified as both a single species with varieties and as multiple distinct species.
My guess is that mine is the true native variety, considering how long I’ve had the plant (hybrids and cultivars are now more readily available than when I was given my Yarrow starts) and that the blooms are a natural snowy white, rather than hybrid pink or yellow. Yarrow’s fine foliage is 5-6 inches tall and acts as a lacy ground cover for most of the year. In early spring, the graceful low-growing foliage grows anew and also sends bloom stalks upward to meet the spring sky. In time, buds appear at the terminal ends of multiple branches.
Depending upon sun amounts received, Yarrow bloom stalks can reach upwards to three feet. Mine all grow with some shade, which is ideal for Yarrow. While Yarrow is a great plant for shade or part shade, in my experience, deep shade will render the plant a full-time, evergreen ground cover, but it abandons all attempts at blooming.
But with some sun, the garden benefits from both beautiful foliage and flowers.
By May and throughout June, the disk flowers open for pollinator business and gardener admiration.
Most of the pollinators I see on Yarrow are of a diminutive sort; these include many types of flies, tiny native bees, and the smaller butterflies.
This Horsefly-like Carpenter bee is one of the larger pollinators to visit my Yarrow blooms.
I grow Yarrow in several areas of my garden and it’s complementary to other members of a perennial garden.
Additionally, Yarrow adds a prairie quality to the summer garden. The prime bloom time lasts about 6-8 weeks, but even when the flowers fade, Yarrow remains handsome.
Into July, a toasty quality appears on Yarrow as the pure white flowers go to seed. As summer settles in with its heat and glaring sun, the flowers decline, seeds develops and Yarrow’s pure white tops turn tan and toasty.
The white Yarrow blooms are hard to improve upon, but as the plant undergoes its seasonal evolution, I don’t mind the transition from blooms to seed. It’s a gradual transition and the plant remains attractive for most of summer.
I’ve seen House Finches and Lesser Goldfinches nibbling at the Yarrow seeds, so along with it acting as a good pollinator plant, other wildlife benefit from this perennial as its growing season advances.
Yarrow’s flower-to-seed heads beauty doesn’t last forever, though. Typically, by the time the flowers are long done and the seed heads are crumbling, the bloom stalks are also bent with age and environmental impacts. After all, they’ve held aloft sweet blooms and nutty seeds for many to enjoy through spring thunder and wind storms and searing summer sun. Bottom line: Yarrow is messy by late summer.
Sometimes, parts of the foliage turns brown in sympathy with the beige seed heads.
Once the bloom stalks have flopped for good, I cut them back. There’s no real art or skill with this pruning, it’s just about cutting the now-brown stalks at or near the ground, which usually reveals new ground cover growth settling in place for the coming seasons: autumn, winter, spring.
In the above photo, the remains of pruned stalks lie disguarded outside of the garden’s limestone border; you can see new Yarrow foliage emerged on the other side of the limestone. This foliage will be the basis of the ground cover which will flush out during autumn and remain evergreen in winter.
In especially dry summers and/or if I haven’t irrigated, the new ground cover foliage endures a breaking-in period where it’s sparse and ratty looking; Yarrow down-time usually occurs in August. Fortunately, the ugly duckling phase doesn’t last long, because the foliage quickly greens up and fills in with help from the shorter days and regular rainfall that September normally brings.
While Yarrow flowers produce seeds (those finches are eating something!), the only spread I’ve observed is with the roots of established plants. In this shot, the foliage has crept out of the border of the garden and into a walkway. I’m tolerant of this creeping action–to a point. When I’ve had enough of Yarrow’s teen-like testing of boundaries, I simply dig out the offenders and toss them into the compost bin or give to another gardener. With healthy attached roots and a smidge of extra watering, Yarrow transplants easily.
By autumn, brilliant green, ferny foliage returns and the groundcover is set for the upcoming cool seasons.
I’ve experienced no insect or disease problems with Yarrow and it’s a drought tolerant plant. Another plus with planting Yarrow is that it is deer resistant. Its foliage and flowers are fragrant and has been used for medicinal purposes. I’m not big on cut flowers, but Yarrow is a nice addition to a vase.
Because it’s somewhat statuesque from April to August and low-to-the ground for the rest of the year, care should be exercised when considering placement of Yarrow: it works in the back of a bed during its peak blooming time, but will be unseen for the remainder of the year. My solution has been to plant all my Yarrow along pathways and pair it with similar sized plants.
Whether you purchase Yarrow or it’s given to you as a passalong plant, treasure it! Yarrow is easy to grow and lovely to look at.
Autumn and Winter: