Common yarrow is a great addition to Pa. gardens

Common yarrow (Achillea millefolium ) is one of my favorite garden perennials. It’s a North American native plant that’s quite commonly found in the wild in its straight species form, which produces white, flat-topped clusters of flowers atop feathery foliage.

In fact, the straight species is so common that in certain regions, it’s considered an invasive weed. However, most gardeners don’t grow the straight species of this plant; instead, they grow one of the many different cultivated selections of yarrow that produce blooms in dozens of different colors.

Yarrow is a tough, drought-resistant plant with blooms in a wide range of colors, including shades of pink, purple, red and yellow. The leaves are hairy and fern-like in their texture, and they have a distinct fragrance.

Yarrow is a member of the aster family of plants. Its bloom clusters consist of hundreds of separate blooms collected together in a flat-topped structure. If you look closely enough at each individual flower, you’ll see they are structured just like other members of the aster family, with a central disk surrounded by petals.

The flat-topped flower clusters are very sturdy, and they make a great landing pad for larger pollinators, such as bumblebees and butterflies.

Yarrow is tolerant of our clay-based soils and thrives in average garden conditions. Ideally, they should receive a minimum of 6 to 8 hours of full sun per day. Less than that, and they’ll need to be staked to keep them from flopping over. Even when this summer bloomer is not in flower, the texture of the foliage is a beautiful addition to the garden. Fully winter hardy down to -30 degrees F, yarrow shrugs off winter like a champ.

Most yarrow cultivars top out around 2 to 3 feet in height, and they spread into a nice-sized clump over the course of several years. Due to their fragranced foliage, yarrow is deer-resistant, though the rabbits in my yard do like to nibble off the leaves from time to time.

There are many colorful varieties of common yarrow. “Cerise Queen” is one of my favorites, with large clusters of hot pink flowers. “Paprika” bears blooms the color of its namesake, and “Summer Wine” produces flower heads that are in a range of colors from brilliant pink to deep maroon.

There are also some compact varieties of yarrow that have come onto the market recently, so if you have a smaller garden, be on the lookout for these short-statured varieties at your favorite local garden center.

The maintenance requirements of common yarrow are minimal. Ensure the plants have enough water during times of drought and stake them if necessary. Deadhead the plants a few times throughout the growing season by cutting the spent bloom stalks down to the base of the plant to encourage more bloom production.

Every five or six years, your yarrow may need to be divided. Signs that the time is right for this task include reduced blooming and crowded plants.