Growing Turkish mullein in a pot

Verbascum bombyciferum is a low-maintenance plant once established, requiring minimal intervention throughout the year. Its low water need means you should water only during prolonged dry spells in the first growing season; established plants are drought-tolerant and rarely need supplementary watering. Overwatering or planting in poorly drained soil is the most common cause of failure, leading to root rot and crown decay. Feed lightly in April or May with a general-purpose granular fertiliser or a handful of blood, fish, and bone scattered around the base of the plant. Avoid high-nitrogen feeds, which promote lush foliage at the expense of flowers and can make plants more prone to flopping. Verbascum grows naturally in poor, stony soils and does not need rich feeding. Mulch with gravel or grit rather than organic matter. A 2–3 cm layer around the crown improves drainage, suppresses weeds, and keeps the neck of the plant dry over winter, which is critical for survival in our damp climate. Avoid bark or compost mulches, which retain moisture. Verbascum bombyciferum is fully hardy in zones 5–9 and needs no winter protection in temperate Europe. The silvery, felted leaves are attractive through winter, though they may look tatted after heavy rain or snow. Remove any rotting foliage in late winter to reduce the risk of fungal disease. Pests are rarely a problem, but verbascum moth caterpillars can occasionally strip foliage in summer. Check plants in June and July and remove caterpillars by hand if you spot them. Powdery mildew may appear in dry summers on older leaves but is rarely serious.