Verbascum

Verbascum dumulosum

Mainly grown as short lived evergreen or semi-evergreen perennials for their tall showy spires of saucer-shaped flowers. Although short-lived, they are easily propagated.

The majority of mulleins grown in the UK are natives of Southern Europe and are mostly hardy in the UK. All varieties need sun and good drainage.

Family: Scrophulariaceae
Botanical Name: Verbascum
Common Names: mullein

Foliage: Deciduous or semi-evergreen. Rosettes of grey/green basal leaves, often hairy. Smaller leaves usually grow up the stems. Some varieties have striking white-felted foliage.
Flowers: Tall spires of close-packed saucer-shaped flowers.
Flowering Period: Early summer through to autumn.
Soil: Moist but well-drained. Chalk or loam. Prefers alkaline pH. Drought tolerant.
Conditions: Full sun, in a south or west facing aspect. Exposed or sheltered position.
Habit: Columnar/upright or bushy.
Type: Annuals, biennials, perennial or short lived perennials.
Hardiness: H6 (hardy in most regions of the UK) to H4

Planting and Growing Verbascum

Best grown in an alkaline (chalky) well-drained light soil, in full sun. Tall species are ideal specimens for the back of a border or in island beds. Most varieties require no staking.

Verbascum are drought resistant, so are ideal for dry gravel gardens. Also a good choice for cottage, wildlife and woodland gardens.

Taking Care of Verbascum

Cut down the faded flower spikes of perennial varieties at the end of the flowering season. Mulch around the base over winter, but do not cover the crown.

Pruning Verbascum

Remove faded flower spikes to induce a second flush.

Pests and Diseases

Susceptible to attack by caterpillars and weevils. Can be affected by powdery mildews.

Propagating Verbascum

Sow seed from March to May.

Biennial verbascums die after flowering and setting their own seed (known as monocarpic).

Cotswold hybrids are both perennial and sterile, so they can only be propagated by root cuttings in winter. Most other named perennial varieties can also be propagated from root cuttings in winter, and some by division in spring.

Popular Varieties of Verbascum Grown in the UK

There are many different cultivars of Verbascum available from medium to dwarf height. Most forms have yellow flowers, but some flower in white or shades of pink and mauve.

V. blattaria (moth mullein) a biennial with pale yellow flowers and purple stamens, set in loose spikes up to 4in (10cm) long. Lancell shaped leaves up to 12in (30cm) long. Requires more damper conditions than most mulleins. Height: 6ft (1.8m), spread: 1ft (30cm).

V. blattaria f. albiflorum as above but with white flowers.

V. 'Blue Lagoon' one of the first true blue flowering verbascum. Perennial. Tall spikes of attractive, open, blue flowers from June to September. Height & spread 1.5ft to 3ft (0.5m to 1m)

V. bombyciferum hardy biennial with spikes of sulphur-yellow flowers rising above oval silvery leaves that are covered in silvery down. Height: 6ft (1.8m), Spread: 2.5ft (75cm). Self seeds freely.

V. chaixii (nettle-leaved mullein) a semi-evergreen perennial with tapering, branched spires, covered by masses of yellow flowers, bearing purple stamens. The 12in long strap leaves are covered with white wooly hairs. Height: 4ft (1.5m), spread: 1.5ft (45cm).

V. densiflorum clear yellow flowers from June to August. Height 4ft, spread 18in.

V. dumulosum, compact evergreen (semi hardy) with yellow flowers, born on 4in (10cm) spires. Oval lance-shaped, woolly leaves. This dwarf variety is ideal for rock gardens. Height: 10in (25cm), spread: 6in (15cm).

V. 'Letitia' forms a mound of grey-felted leaves topped with spires of yellow flowers from early to late summer. Requires protection from winter wet. Height & spread 1.5ft to 3ft (0.5m to 1m)

V. phoeniceum (purple mullein) biennial or short-lived evergreen perennial with delicate flower spires in shades of pink, purple and white. A good self seeder. Height: 3ft (1m), spread: 1ft (30cm).