Brighten your landscape with the golden flowers of fernleaf yarrow (Achillea filipendulina). This cousin of common yarrow creates a strong and stately presence in the garden. It grows up to 5 feet tall with sturdy flowering stems topped by flat, bright gold flower heads. Fernleaf yarrow is sometimes called yellow yarrow, although this name may stir confusion because many yellow yarrows exist within the common yarrow group.
Growing fernleaf yarrow isn’t difficult. Like its cousin common yarrow (Achillea millefolium), this yellow yarrow grows best in full sun. It can grow in partial shade, but the tall stems stretch even higher and become weak, which means you’ll have to stake plants. Flower numbers decrease in shade, as well.
It’s pretty typical to need to stake fernleaf or yellow yarrow because large flowerheads make the tall stems top heavy. These flowers differ from common yarrow in that the individual blooms are packed so tightly together that they almost form a single, plate-like mass. It’s a heavy flowerhead, and more so because it measures about 4 inches across.
Deadheading doesn’t encourage yellow yarrow to rebloom in fall. Still, it’s a good idea to remove spent blooms to help tidy the garden and prevent self-sowing. Yellow yarrow spreads by self-sowing and rhizomes or underground stems, although it’s not as aggressive in its spreading tendencies as common yarrow. After removing spent blooms, you’ll have a tuft of green ferny leaves that look attractive until frost.
Choose a planting site with average, well-drained soil or sandy, lean soil. Avoid soils that are rich and fertile or filled with heavy clay. Try to choose a site that’s protected from wind. If your garden experiences steady wind, plan to stake yellow yarrow clumps once flower buds appear. Plants are hardy in Zones 3 to 10.
Like other yarrows, fernleaf or yellow yarrow opens flowers that beckon pollinators. Use fernleaf yarrow in wildlife or butterfly gardens or as part of a pollinator-friendly planting. This yarrow also boasts strong drought tolerance, making it a good candidate for xeriscape gardens.
Because of their sturdy construction, these achillea flowers dry very well. If kept in away from direct sunlight, the dried blooms can retain their color for years. To dry yellow yarrow blooms, harvest flowers when all of the individual blossoms have opened but before the color fades even a smidge. Dry flowers by standing stems in a vase or by bundling stems together and hanging them upside down in a dark, airy place.
The center of yellow yarrow clumps tend to die out after a few years. Plan to divide clumps every three to four years. Dig the entire clump and discard any dead center sections. Save the living outer edges of clumps for replanting.