Yarrow, sometimes known as sun fern for its high light requirement and fern-like foliage, is an herbaceous perennial plant valued for its aromatic, ornamental flowers. The yarrow plant can reach up to 3 feet in height and develops flat, dense clusters of flowers in spring, summer and fall. Yarrow flowers are most often white, but they can also be yellow, orange, pink or red. Yarrow plants are hardy in zones 3 through 9, and require very little care to thrive in the home garden.
Purchase yarrow plants in spring or fall from a nursery or garden center. They are typically available as started plants in 1- to 6-gallon containers. Choose a planting location that receives full sun and has well-drained soil of average fertility.
Prepare the site by cultivating the soil to a depth of 6 inches with a garden tiller. Dig a planting hole of equal depth and twice as wide as the plant's current growing container. Place the yarrow plant into the hole, back-fill with soil and water thoroughly. Space plants 18 inches apart to allow room for growth.
Water yarrow plants only after the soil has completely dried, about once per week during spring and summer. Reduce the frequency of watering during fall and winter to once every two weeks, or any time the top 2 to 3 inches of soil are dry to the touch.
Remove spent yarrow flowers after they have faded to encourage further blooming. Cut back the dead flower clusters with pruning shears or pinch off with your fingers if possible. In some cases, deadheading may result in a second bloom in fall.
Stake tall yarrow cultivars to prevent them from falling over or drooping when they become too tall. Place a flower stake in the ground 1 to 2 inches from the base of the plant and secure it loosely to the stake with garden twine for the best results.
Things You Will Need
- Garden tiller
- Pruning shears
- Flower stakes
- Garden twine
- Yarrow flowers may be cut for flower arrangements if desired, and this will have the same effect as deadheading.
- Divide yarrow plants once every 2 to 3 years to increase vigor and prevent the plants from becoming too crowded.
- No supplemental fertilization of yarrow plants is required. Blooming and longevity may suffer if the plants are fertilized.
- Do not apply water to yarrow plants on weeks that receive at least 1 inch of natural rainfall. Yarrow cannot tolerate soggy soils, and too much water can result in weak plants prone to fungal diseases.