IF you’re looking for height to add to your borders, verbascum is one of the best plant choices to take you from early summer through to its last throes. It combines cottage-garden prettiness with architectural drama and, with timely flowers arriving in late May, it’s not surprising that this stylish plant often graces Chelsea Flower Show gardens.
Yet verbascums will happily find a home in everyday garden borders, too. Whether you’re cultivating an exuberant cottage-garden look, or a sparser, drought-tolerant, gravel garden style, these plants will provide long-lasting summer colour.
Cutting back flowering spikes
Verbascums can be short-lived hardy perennial plants, biennials that give you great foliage interest in the first season followed by colourful blooms the next summer or slightly fussy cultivars that might not go past one season of glory. Cutting back flowering spikes will encourage more flowers through the summer and help control the prolific self-seeding types, which can become a bit invasive.
Manage the continuity of your favourite verbascum by encouraging a bit of self-seeding, learning to recognise the young seedlings and moving them before they establish themselves in the wrong spot. It’s also worth saving seed to sow for succession.
The fancier hybrids are sterile and won’t set seed, but they can be propagated by root cuttings. Margaret Mason from the Hardy Plant Society advises digging up the plants after flowering, selecting roots about 2-4in (5-10cm) long and cutting small sections, then planting them into sandy, gritty compost, level with the surface. Watch for shoots to appear and then repot and plant out the following spring after the last frost. It’s perhaps a task for the more experienced gardener, but fun to try.
Foliage textures and colours
Verbascums work well in combination with other summer verticals such as delphiniums, hollyhocks and foxgloves. Also use them for their foliage textures and the selection of colours that will complement both hot and cool colour schemes. They make good companions for many summer-flowering perennials, including architectural cardoons, as well as salvias, alliums, geums, fennel, eryngiums, daisies and umbellifers.
As we move into early summer, it’s the perfect time to reassess and tweak borders, fill gaps and manage the composition of textures, colours and structure. Use verbascums, repeated through your borders, to lead the view along or down the garden.
9 pastel shades
Verbascum ‘Southern Charm’
This is a shorter-lived perennial form, but it is the height of fashionable colouring, all shades of soft pink and café au lait. You’ll be rewarded with flowers from May to August, but to encourage repeat blooming, cut off the central flower spike after flowering. HxS: 36x18in (90x45cm).
Verbascum chaixii ‘Album’
The chaixii verbascums are longer lived than other species, so this is reliable and easy to grow and good for dry, sunny locations. With typical grey-green, felty rosettes of leaves, the emerging spires of ‘Album’ are white with dark-pink centres. HxS: 3x2ft (90x60cm).
Verbascum ‘Kynaston’
The white blooms that clothe the spires of this tall cultivar make an imposing tower in mixed borders. Combine with plants such as hollyhocks, umbellifers and strong daisy types such as echinacea. It will need staking for support. HxS: 6½x3ft (2mx90cm).
Verbascum ‘Caribbean Crush’
This apricot-toned mullein is a hybrid of V. bombyciferum, with furry grey leaves that make an attractive rosette. Winter hardy, the tall stems of summer flowers make a real statement through the summer, but may need staking. HxS: 4x2ft (1.2mx60cm).
Verbascum (Cotswold Group)
‘Gainsborough’ AGM
‘Gainsborough’ is a beautiful and elegant pale-yellow flower, and this mid-height Verbascum makes a great companion emerging alongside blue and purple flowering salvias or mounds of nepeta. Mulch over winter. HxS: 5ftx15in (1.5mx40cm).
Verbascum phoeniceum ‘Rosetta’
Also known as the purple mullein, this is the source of many of the pink, purple and white-coloured hybrids. ‘Rosetta’ is a hardy perennial, flowering from May to August. It works well towards the front of borders, or in larger containers. HxS: 3x1ft (90x30cm).
Verbascum ‘Helen Johnson’
A famous verbascum, this was one of those in-vogue plants at the flower shows and sparked a bit of a craze although many found it too short lived. Its beautiful colouring makes it desirable, but you might have to treat it like an annual plant, unless you take root cuttings after flowering. HxS: 5ftx15in (1.5mx40cm).
Verbascum ‘Pink Domino’ AGM
The flowers of ‘Pink Domino’ are a little more open and the tall single spires look very painterly in mixed summer borders. It looks good combined with eryngiums and campanulas for contrast. A reliable hybrid, good for poorer soils with a more alkaline pH, so it would also suit a gravel garden. HxS: 4x2ft (120x60cm).
‘Cotswold Beauty’
This is indeed a beauty, with apricottoned flowers with dark-pink centres. It has a slightly shorter flowering season, blooming through May and June, so team with alliums, stipa and miscanthus for an elegant meadowy look. HxS: 4x1ft (120x30cm).
4 stronger shades
Verbascum ‘Firedance’
A new hybrid, with flowers in a gorgeous dark terracotta-red shade from June to August, this would make a great addition to hot-coloured summer borders. This is billed as a hardy, short-lived perennial and is a medium-height variety. Take root cuttings after to ensure continuity. HxS: 39x12in (1mx30cm).
Verbascum phoeniceum ‘Violet Hill’
This is a sturdy and long-flowering cultivar, blooming into September. These tend to be longer lived and it has good resistance to slugs and rabbits. There’s no need to stake it and it prefers poor, dry soil in the sun, although it will tolerate light shade. Winter hardy. HxS: 24-32x18-24in (60-80x45-60cm).
Verbascum ‘Clementine’
This is another longer lasting cultivar, tolerant of coastal garden conditions and with proven winter hardiness. A glowing, warm-toned verbascum that epitomises summer with purple-eyed, warm orange-brown flowers. Reputedly longer lived than many. HxS: 32-60x18-24in (80-150x45-60cm).
Verbascum nigrum
Also known as ‘dark mullein’, this refers to the black root of this species rather than the flowers, which are bright-yellow with a maroon centre. A reliable self-seeder, although your original plant might be short lived, it will leave a good legacy. HxS: 3x2ft (90x60cm).
3 giant verbascums
Verbascum bombyciferum
This hardy biennial will produce large rosettes of felted grey green leaves in the first year with the tall candelabralike flower spikes emerging in the second growing season. In Beth Chatto’s gravel garden, it’s used to great effect with its architectural form. A good self-seeder. HxS: 6x2½ft (1.8mx75cm).
Verbascum thapsus This has great value as an ornamental and pollinator friendly plant, as well as its medicinal properties. It will self-seed if allowed, or you can save the seed to maintain more controlled continuity over where it grows. Good for a wildlife border, it needs well-drained soil and plenty of direct sunshine. HxS: 6½ftx16in (2mx50cm).
Verbascum olympicum
Greek mullein is another towering yellow-flowered species that will selfseed generously. It’s a good idea to learn to spot stray seedlings when small if you want to reposition them; once established as larger volunteer seedlings, they don’t transplant happily. It is good for dry, gravel gardens. HxS: 10x4ft (3mx1.2m).
Frequently asked questions
What is verbascum used for?
VERBASCUMS have long been used as a herbal remedy. Mullein, as it is also known, has been used to treat respiratory problems and urinary tract infections, as well as general healing of wounds. V. thapsus is the source and scientific studies back up the value of the traditional uses. Wild verbascum stems were also dipped in tallow for use as torches. They are known as ‘the Candlewick plant’ as the downy foliage was used to make wicks in oil lamps before cotton.
Where should I plant verbascum?
THESE plants can be grown in a range of soils from fertile borders to gravel gardens. Native species are more tolerant of loamy or clay soils and the long tap root helps them cope with drought. Mediterranean types prefer sharply drained soil, neutral to alkaline in pH, and work well in gravel or scree. Think tall verbascums towering above mounded pinks, armeria, lavenders, santolinas and grasses. They also work well in mixed borders. All types of verbascum need full sun to thrive.
How tall do verbascums grow?
VERBASCUMS can range in height from approximately 2ft (60cm), and many of the chaixii and phoenicium types will work well towards the front of borders or in larger containers. The tall specimens grow to well over 6ft (2m), such as V. thapsus, V. olympicum or V. bombyciferum with its sulphuryellow flowers and felted leaves. Use these mid border or at the back, or exploit their architectural form in gravel plantings. Some taller species may need staking.