Yarrow, botanically known as Achillea millefolium, is a garden perennial often referred to as “yellar.” This resilient plant is a popular choice for gardeners due to its straightforward care requirements and lasting appeal. It offers hardiness, visual interest, and ecological benefits, making it a fitting addition to various garden styles.
Understanding Yarrow
Yarrow is an herbaceous perennial in the Asteraceae family. Its distinctive features include aromatic, fern-like foliage and flat-topped clusters of tiny flowers. These flowers, which bloom from late spring through fall, attract beneficial insects such as butterflies and bees. Originating from temperate regions, yarrow adapts to a range of climates.
This plant is valued for its drought tolerance, requiring minimal watering once established. It also thrives in less-than-ideal soil, making it a low-maintenance option. Common yarrow often produces white flowers, but cultivated varieties offer a spectrum of colors including yellow, pink, red, and orange.
Planting Yarrow Successfully
Establishing yarrow begins with selecting a site that receives full sun (at least six to eight hours daily). This is crucial for compact growth and abundant flowering. In partial shade, yarrow may become leggy and produce fewer blooms. Yarrow performs best in well-drained soil, tolerating various compositions, but avoiding constantly wet conditions prevents root issues.
When preparing the planting area, loosen the soil to a depth of 12 to 15 inches. Amend it with organic matter to improve drainage if necessary. For nursery starts, dig a hole slightly deeper and twice as wide as the root ball. Position the plant so the crown is level with the surrounding soil, then backfill, gently tamping to remove air pockets, and water thoroughly.
If planting from seed, sow them on the soil surface or at a shallow depth of about 1/4 inch, as light is often required for germination. Seeds can be started indoors eight to ten weeks before the last frost or direct-sown outdoors in early spring or fall. Space yarrow plants 1 to 2 feet apart, depending on the variety, to allow for adequate growth.
Ongoing Yarrow Care
Once established, yarrow requires minimal ongoing attention. Watering needs are low; yarrow is drought-tolerant and only needs about a half-inch of water weekly during prolonged dry periods, or if rainfall is less than one inch per week. Overwatering should be avoided, as it can lead to root rot. Allowing the soil to dry out completely between waterings is a good practice.
Yarrow thrives in average to poor soil and does not require extensive fertilization. Overly rich soil can lead to leggy growth and fewer flowers. A light application of a balanced slow-release fertilizer in early spring or a thin layer of compost can be beneficial.
Deadheading spent flowers encourages continuous blooms and prevents aggressive self-seeding. To deadhead, cut the stem back above a lateral bud or by up to half its size after the first flush of blooms. For overall plant health, cut back the entire plant to its basal foliage in late fall or early spring before new growth begins.
Multiplying Your Yarrow Plants
Yarrow is straightforward to propagate, allowing gardeners to expand their collection. Division is a common and effective method, particularly for established clumps, best performed in early spring before new growth or in the fall after flowering. This process invigorates older plants and manages their spread, as yarrow expands through its rhizomatous root system. When dividing, gently separate sections, ensuring each piece has healthy roots and stems, then replant them at the same depth as the original plant.
Growing yarrow from seed is another viable option. Seeds require light for germination and should be sown on the surface of moist seed-starting mix or lightly pressed into the soil. Cold stratification for about a month can improve germination rates for some varieties. Seeds germinate within 10 to 14 days when kept at temperatures between 65-72°F (18-22°C).
Stem cuttings can replicate desirable varieties. Plant cuttings into a well-draining rooting medium, providing consistent moisture until roots develop.
Troubleshooting Yarrow Problems
Yarrow is generally resilient, but a few issues can arise. Overwatering is a common concern, as yarrow prefers dry conditions and can develop root rot in consistently wet soil. Symptoms like yellowing leaves and wilting can resemble underwatering. Ensuring well-drained soil and allowing the soil to dry between waterings prevents this.
Fungal diseases like powdery mildew can appear, especially in humid conditions or poor air circulation. This manifests as a white, powdery coating on leaves. Proper spacing and planting in full sun can help mitigate this.
Yarrow is generally pest-resistant, but aphids or spittlebugs may be present. A strong spray of water can dislodge these pests. Legginess or flopping stems can occur if yarrow is planted in overly rich soil or insufficient sunlight; choosing a site with lean soil and full sun helps maintain a more compact growth habit. Regular pruning prevents legginess and encourages sturdier stems.