Mouse-ear hawkweed: complete guide

Mouse-ear hawkweed (Pilosella cymosa), also called cymose hawkweed, is a robust perennial from the daisy family. The plant is native to Europe extending to West Siberia and Kazakhstan, growing in dry mountain areas, steppes and grasslands. Mouse-ear hawkweed is a low-growing plant reaching 20-60 centimeters tall with long, narrow leaves forming ground-level rosette clusters. During June through July the plant produces bright yellow daisy-like flower heads arranged in branched clusters, hence the name 'cymosa'.

The plant is extremely hardy in USDA zones 3-9, meaning it tolerates temperatures down to -35 degrees Celsius. The growing season runs April through October in temperate climates. The plant self-seeds via plumed seeds, so removing faded flowers is wise if natural spread is undesired. Under favorable conditions mouse-ear hawkweed can become fairly invasive, though this may be desirable for wildflower ground cover applications.

Mouse-ear hawkweed thrives in well-drained, slightly alkaline soil with pH 7.5 to 8. The plant grows on nutrient-poor soil and is highly tolerant of drought once established. Prefers locations with full sun to partial shade; minimum 6 hours direct sunlight is ideal. In high-rainfall areas the plant may prefer elevated planting positions or very well-drained soil to prevent root rot. In containers an alpine potting mix of grit, sand and compost in 2:1:1 ratio works well.

Watering is minimal once the plant is established. During the growing season lightly moist soil can be maintained, but the plant tolerates dry periods. Overwatering is actually more damaging than underwatering. In dry summers watering once every two weeks may suffice. In winter the plant goes dormant and requires virtually no water.

Maintenance of mouse-ear hawkweed is minimal. Remove faded flower heads in June-July to limit self-seeding or allow it if desired. Annual feeding is unnecessary on nutrient-poor soil. On rich soil a balanced fertilizer like 10-10-10 once in early spring can be given. Division can be performed every three to four years in spring or autumn for rejuvenated plants.

Mouse-ear hawkweed is excellent for border fronts, alpine troughs, and dry grassland areas. In northern Europe it grows wild in cooler upland regions. In gardens it partners well with saxifrages, lavenders (Lavandula) and hardy geraniums. Pest damage is uncommon though slug damage can occur in wet seasons. The plant is reliable and requires minimal intervention for decades of garden display.