Meet a common wildflower that's become a beloved ornamental flower.
Meet the wildflower that goes by a host of names. Common yarrow, also known as western yarrow or milfoil, goes by the botanical name of Achillea millefolium. This native beauty is a common roadside weed across North America. In the perennial garden, common yarrow shines as a low-maintenance, drought-tolerant butterfly plant.
Common yarrow boasts a host of desirable qualities, including strong winter hardiness. Most members of the Achillea yarrow clan are hardy from Zones 2 or 3 to 10, although they don’t hold up particularly well in high heat coupled with high humidity. The combination tends to cause plants to melt away in the heart in of summer.
Plants thrive in full sun and high heat. Give common yarrow average, well-drained soil, although plants can grow in lean, gravelly soil. If soil is too rich in nutrition, common yarrow tends to grow taller with weaker stems. In rich soil, yarrow clumps flop open and stems sprawl instead of standing upright.
Established clumps of common yarrow are drought-tolerant. They make a great addition to xeriscape garden designs or water-wise landscapes. During periods of prolonged drought, it’s a good idea to water common yarrow to prevent plants from dying. Common yarrow tolerates salt, making it a strong choice for a seaside garden. Plant size comes in at 18 to 24 inches tall and 24 to 36 inches wide.
Yarrow opens flowers in summer over a period of four to six weeks or more. A host of varieties and hybrids exist, extending this wildflower’s color range from white or blush pink to a rainbow of hues. Pastels, bold tones and regal gold all grace the common yarrow clan. The varieties tame the wildflower’s growing habit somewhat, curtailing its tendency to spread.
Common yarrow spreads by self-sowing and underground stems. Self-sowing is easy to control—simply snip spent blooms. It’s important to remove spent flowers in yarrow varieties and hybrids to prevent plants from reverting to the parent form. (This happens because this group of plants readily cross breeds.)
Some gardeners prune dead flowers to encourage a second set of blooms to form right away. Others clip spent flower stalks back to the leafy base of plants. This results in a fresh flush of leafy growth, followed by a few fall flowers, especially in warmer regions.
To control spreading by underground stems, just pull up new sprouts—and the attached stem, which is just below the soil surface—as they wander out of bounds. Do this in early spring and during the growing season. It’s easier to pull up spreading stems after a rain, when soil is soft.
Include common yarrow in butterfly gardens and cutting gardens. Cut yarrow flowers last three to five days in a vase. Gather flowers just as the last flower buds on the flat head have opened, but before any blooms have started to fade.