Verbascum - Growing Guide

Mullein

Quite a number of the species and varieties of Verbascum grown in our gardens are biennials or very short-lived plants. Once the tall flowering spike is over many of the common Verbascum produce huge quantities of seed which is widely scattered in the wind and germinates naturally in borders and crevices or patio cracks nearby the original plant. A bit like Echium pininana they therefore become self-perpetuating in the garden.

The varieties which Burncoose offers on its website are not typically biennials. The species are rosette forming evergreen or semi-evergreen perennials. If the central plant in a rosette flowers profusely that plant may die off in its second year, but it will leave other plants within the rosette to carry on. The named varieties (as opposed to the pure species) are made of sterner stuff and will carry on growing as clumps in the garden year after year. 

Verbascum thrive in hot, dry, sunny locations where the soil may be poor. At Ventnor Botanic Garden the various species grown there have crossed up and naturalised themselves on rocky banks and dry borders or rockeries to provide a continuous year on year show of white and yellow flower spikes in June and July.

Taller growing Verbascum will probably require some support for their flower spikes perhaps only with a cane. In fertile soil, where Verbascum grow more quickly and spectacularly, or in pots supports become even more important.

If you have several different Verbascum in your garden or a neighbour’s, the seedlings will produce a mixed result. Propagation of perennials is easiest by division in spring.

The two species which we grow are:

V. olympicum can be monocarpic in that its flowering stems may die after setting seed but smaller younger offsets around it will survive. Sometimes plants can take two to three years to flower and smaller plants often survive a small flowering. The flower spikes can grow up to 6ft in height and are covered in yellow saucer shaped flowers. This species is native to Greece but widely seen growing wild in south coast communities.

V. phoeniceum, purple mullein, is a similar short-lived perennial which behaves in much the same way. Its flower spikes can grow to around 4ft, and it has scalloped or wrinkled leaves. Its flowers can be white through to pink.

Our named varieties of Verbascum are:

V. ‘Clementine’ – coppery orange flowers

V. ‘Firedance’ – fiery red flowers

V. ‘Helen Johnson’ – light pinkish-brown

V. ‘Kynaston’ – white flowers with an orange eye

V. Pink Domino’ – deep rose pink flowers

These all grow up to 3ft tall with a spread of about 12in to the evergreen rosette. They all flower from early to late summer.