Betony (Stachys officinalis) is a clump-forming European perennial in the mint family, grown for dense whorls of bright magenta-pink flowers on upright stems rising above a rosette of wrinkled, scalloped leaves. It is long-lived, tolerates neglect, and suits cottage, meadow, and pollinator plantings. The cultivar 'Hummelo' holds the RHS Award of Garden Merit and is among the most reliable selections for garden use.
Grows best in full sun to light shade in well-drained soil; it handles dry spells once established and performs poorly in waterlogged ground. Clumps spread slowly by rhizomes and benefit from division every three to four years to stay vigorous. Prefers a neutral to slightly alkaline pH and is cold-hardy enough to overwinter with no protection through zone 4.
Betony has one of the longest medicinal records of any European herb, cited in Anglo-Saxon herbals and Roman pharmacopoeias. It was traditionally prepared as a tea for headaches, nervous complaints, and digestive upset and remains in use in Western herbalism for those purposes.
Powdery mildew
White or grey powdery coating on leaves - usually starting on older growth in humid conditions or when nights cool.
Improve air circulation by thinning plants. Apply neem oil or potassium bicarbonate spray at first sign. Avoid overhead watering.
Root rot
Plants wilt, yellow, and stunt even in moist soil; lower stems and roots turn brown, soft, and mushy and the plant may collapse. Most common in heavy, wet, or poorly drained ground.
Improve drainage and stop overwatering, and never plant too deep. Lift and destroy badly affected plants along with the soil around the roots. Grow in raised or free-draining beds to prevent it returning.