<em>Verbascum</em>, mullein: to plant, to grow and to care for

Description and Botany

The mulleins comprise nearly 360 biennial or perennial species, often villous or pubescent. They occur mainly in Europe and Asia, and also in North Africa. Greatest species diversity is found in Mediterranean region. In France, 13 species occur naturally, including Verbascum thapsus. They grow especially on fallow land, prairies, rocky places and along path edges…

Best known is Verbascum thapsus, also called white mullein. It is a biennial: in first year it produces a rosette of leaves, then in second year a flowering stem. It then dies, but can self-seed. Sometimes Verbascum thapsus appears spontaneously in gardens, self-seeding like a very ornamental weed that gardeners may be glad to keep!

White mullein, Verbascum thapsus, is a ruderal plant: a pioneer plant that establishes on disturbed, fallow or unstable ground. It is among the first plants to arrive when soil is still bare. Mullein readily self-seeds. Seeds and young seedlings need bare soil to develop, which is why it will not colonise spontaneously where a true vegetative cover already exists.

Verbascum thapsus has many vernacular names: Our Lady’s candle, white mullein, Saint Fiacre’s herb, mullein… In former times flowering stalks of Verbascum thapsus were used as torches after being dipped in resin, suet or wax, hence name Our Lady’s candle. Etymologically, Verbascum may be a deformation of Latin Barbascum: “bearded”, an allusion to stamens bearing filaments covered with hairs. Specific name thapsus comes from Thapsos, an ancient town in Sicily. Name “mullein” would come from mol: “soft”, referring to plant’s foliage.

Verbascum thapsus: botanical illustration

Mullein belongs to family Scrophulariaceae (nearly 1,600 species). This family includes Buddleias (butterfly bushes), nemesias and diascias, plants often grown in gardens for their abundant, colourful flowering.

Verbascum have an erect, very upright habit. They range from about 30 cm for smallest to 2 m for tallest (Verbascum thapsus, notably). There are attractive dwarf varieties, such as ‘Sugar Plum’, well suited to planting at front of a border, on an edge, or in a large pot to enliven a terrace, for example.

Mullein begins by forming a rosette of leaves at ground level, then sends up an upright flowering stem. This stem is sturdy and thick, giving plant a rather rigid aspect. In biennials, such as Verbascum thapsus, rosette forms in first year and flowering stem appears in second year. Winter cold makes plant able to flower the following year. Plant will then disappear after dispersing its seeds.

Around June, plant sends up one or more flowering stems from centre of rosette. White mullein, Verbascum thapsus, usually produces a single stem. There are also very different species, such as Verbascum acaule, which has no flowering stem! Its flowers appear at rosette level.

Mullein flowers throughout summer, generally from June to August–September. Flowering is long, it can last three months. Flowers open progressively, one after another, usually from base of spike towards tip. Often only a few flowers are open at any one time on a flowering spike. Each flower is fairly short-lived, generally lasting only one day in Verbascum thapsus… But there are so many flowers on a spike that they follow each other continuously, allowing prolonged flowering!

Mullein bears long, dense spikes or clusters made up of very large numbers of flowers. They can reach up to one metre in length and are more or less branched. They are little branched in Verbascum thapsus, but very branched in Verbascum olympicum… giving the plant a quite different silhouette!

Flowers have a relatively regular shape, with radial symmetry… which is rather rare for a member of Scrophulariaceae! They are cup-shaped, well open towards exterior. Flowers are generally 2 to 4 cm in diameter, and have five rounded petals. Petals are fused at base into a very short tube and surrounded by five sepals. At centre are five stamens, fairly decorative. Sometimes these bear long coloured hairs on their filaments, as in Verbascum nigrum!

Flowers are most often yellow or white… but many horticultural varieties have been created, now offering a range of colours: pink, mauve, violet, orange, coppery, even red… There is even a blue-flowered Verbascum: ‘Blue Lagoon’! Its flowering slightly resembles delphinium spikes. In Verbascum thapsus, flowers are yellow and stamens orange.

Mullein flowers can display superb shades, usually darker at the centre. They are very contrasting in mullein ‘Cotswold Queen’! Likewise, in centre of flower stamens often show lovely orange or purplish colours. Flowers of Verbascum nigrum carry violet–purplish stamens!

Mullein is an excellent melliferous plant. Many insects, including bees and hoverflies, visit the flowers. Plant mullein to create a border favourable to insects and to biodiversity!

Faded inflorescences persist on plant for a long time. They remain through winter. For aesthetic reasons, you may cut them.

Mulleins come in a lovely range of colours! From left to right, Verbascum ‘Clementine’, Verbascum ‘Cotswold Queen’, Verbascum nigrum ‘Album’ and Verbascum phoeniceum (photo Geaster)

Mullein has a very elegant silhouette, with large leaves spreading around the plant base, and a tall, vertical flowering spike.

Mullein forms a wide rosette of leaves at ground level, which can reach up to 60 cm across! Rosette of Verbascum thapsus persists through winter. Plant is thus decorative all year round. Basal leaves measure between 30 and 50 cm long, while those of garden varieties are generally smaller.

Mullein also has cauline leaves, placed on stem in an alternate arrangement (one after another), smaller than basal leaves. Generally, the higher up the stem, the smaller the leaves.

Aside from its flowering, mullein is appreciated for its velvety, pubescent foliage. Leaves are simple, entire, ovate. They are thick yet remain supple. They are covered with a white felt, giving a very velvety, soft texture. Hairs on leaves lend the plant a more or less silvery tint… Species Verbascum bombyciferum is particularly notable for its superb grey colour!

Downy foliage of Verbascum thapsus and of Verbascum phlomoides

Mullein has a taproot, anchoring it firmly and allowing it to draw water from depth, which makes plant quite drought-resistant.

Fruit of mullein is a capsule that opens by two valves when ripe. Each mullein produces many capsules each containing hundreds of tiny seeds. Thus a single plant can easily produce more than 100,000 seeds! Moreover, seeds remain viable for several decades!

Verbascum thapsus tends to self-seed if spent flowering stems are left in place. Seeds germinate on bare soil, in an unoccupied space. They do not move far: if new seedlings appear, they will probably be beside parent plant.

Capsules (photo Didier Descouens – Museum de Toulouse) and seeds of Verbascum blattaria

The main varieties of Verbascum

Most popular varieties

Our favourite varieties

Other varieties to discover

Verbascum Pink Domino - Mullein

This variety has soft pink flowers, shaded with deeper pink at the centre. Ideal alongside roses for a very romantic garden! Recipient of the Award of Garden Merit from the Royal Horticultural Society (RHS).

• Flowering time July to September
• Height at maturity 1 m

See the product sheet

Verbascum Southern Charm - Mullein

This mullein has pastel flowering in shades of soft pink, beige and apricot... With very soft, warm tones, it will find its place in a cottage or vintage-style garden.

• Flowering time July to September
• Height at maturity 70 cm

See the product sheet

Verbascum Sugar Plum - Mullein

This dwarf variety produces abundant mauve-pink flowering, contrasted by a purple centre in the flower. Suitable for a border, at front of a bed, or planted in a large container on a patio.

• Flowering time June to September
• Height at maturity 40 cm

See the product sheet

 

Verbascum thapsus - Mullein

This is the true mullein as found in the wild! It offers golden-yellow flowering that is extremely bright, and downy foliage.

• Flowering time July to September
• Height at maturity 1,75 m

See the product sheet

Verbascum phoeniceum Flush of White - Mullein

This mullein has a superb pure-white flowering, very elegant! Flowers are slightly tinged by soft yellow stamens at the centre.

• Flowering time July, August
• Height at maturity 80 cm

See the product sheet

Verbascum Jackie - Mullein

This is a compact variety with soft, warm flowering. Flowers are apricot-coloured, darker at the centre, and display beautiful shading.

• Flowering time July to October
• Height at maturity 35 cm

See the product sheet

Verbascum bombyciferum Polarsommer - Mullein

An unusual mullein with very woolly leaves, giving the plant a superb silvery hue! It also produces yellow flowering.

• Flowering time August to October
• Height at maturity 1,60 m

See the product sheet

Verbascum Cotswold Queen - Mullein

This mullein has a striking golden-yellow flowering, sharply contrasted by a very dark purplish centre in the flower!

• Flowering time July to September
• Height at maturity 1,50 m

See the product sheet

Planting Verbascum

Where to plant?

We recommend planting mullein in full sun. This exposure suits it best, ensuring abundant flowering. Some varieties also do well in partial shade, provided light levels are fairly high.

Overall, mullein is an undemanding plant, but soil must be well drained. It dislikes soils that retain water, especially heavy, compact soils… Avoid if ground is particularly clayey! (unless planting in a container or seriously improving drainage). It also likes calcareous, alkaline soil.

As mullein favours dry, poor, stony ground, you can easily plant it in a rockery. It is also ideal for planting on slopes.

Mullein is quite tall when in flower, which is why it is better placed at the back of borders, behind lower plants. It will bring structure and verticality. However, there are a few dwarf varieties, such as ‘Sugar Plum’, which can be placed at the edge, at the front of a border, or in a pot or container.

Being an easy plant that needs little and favours rocky, even sandy ground, you can use it to green a spot that is difficult to landscape. It is ideal for filling space (being very sizeable), even on poor soil!

When to plant?

It is preferable to plant mullein in spring, around April, although planting can also be carried out in autumn.

How to plant?

Mulleins form large rosettes of leaves: we suggest spacing smaller varieties about 40 cm apart, but allow at least 70–80 cm between larger ones. Avoid planting too densely!

1. Dig a planting hole. Feel free to add draining materials, such as gravel or coarse sand… You can also plant on a mound to help water drain away.
2. Remove rootball from pot and plant your Verbascum. Collar should be at soil level, or slightly above (to prevent water pooling at the collar).
3. Replace soil around plant and firm down.
4. Water thoroughly.

Care

Mullein requires very little maintenance. It tolerates drought well, even in summer. It generally needs no watering and does not require fertiliser either.

We suggest laying a layer of mulch around base of your mullein plants. This will slow weed growth.

Because they have thick, stiff stems, it is generally unnecessary to stake mullein unless planted in particularly rich soil or exposed to winds.

Cut flower spikes when spent. You can leave a few in place if you want the plant to self-seed.

Mullein is a hardy plant, not very susceptible to diseases and pests. It can occasionally be affected by powdery mildew, a fungal disease recognisable by white spots on leaves. If you notice its presence, we recommend removing affected parts and treating with a sulphur-based solution. Leaves may also be eaten by caterpillars, notably by the mullein moth caterpillar (Cucullia verbasci).

Propagation

Best technique to multiply Mullein is sowing. It even sometimes self-seeds if flower stems are left in place.

Sowing

You can sow Verbascum seeds in spring, in April or May. Horticultural varieties, however, may produce flowers slightly different from original variety. By contrast, Verbascum seeds keep very well: they remain viable for decades.

Mullein has tiny seeds: we recommend mixing them with sand to make handling easier. As they need light to germinate, do not cover them with substrate afterwards.

1. Prepare seed tray or module tray by filling it with potting compost (you can add a little sand to make it more free-draining). Water so substrate is well moist.
2. Mix seeds with sand to distribute them more easily over compost.
3. Scatter them on surface, but do not cover them!
4. Firm down gently.
5. Place tray under cold frame.

Substrate must stay slightly moist until germination, which will occur after one or two weeks. You can plant out in ground after last frosts, or in early autumn.

As Verbascum thapsus is a biennial, it will produce a rosette of leaves in first year, then flower in following year. Some varieties (such as ‘Southern Charm’) may flower in first year.

You can also sow Mullein in autumn and transplant in spring.

Finally, it is possible to sow Verbascum directly in ground, but if rosette of leaves that forms is still small when winter arrives, it may be killed by cold. If it has had time to develop well, it will survive.

Companion planting with mulleins in the garden

Mulleins are perfect for integrating into a dry, rocky garden. You can pair them with other plants that tolerate drought and accept poor, stony soils. Plant them with achilleas, Eryngium, teasels (Dipsacus fullonum), euphorbias… Add a few clumps of grasses, such as Stipa tenuifolia. They can also be combined with Mediterranean plants, such as Jerusalem sages (Phlomis fruticosa), lavender, rosemary, grasses, Euphorbia characias…

Verbascums can fit into a dry, mineral garden. Scene with Verbascum ‘Polarsommer’, Eryngium oliverianum, Centranthus ruber, Salvia caradonna and Stipa tenuifolia (photo AC – Nathalie Pasquel – MAP – Landscape designer Robert Myers) / Salvia nemorosa ‘Caradonna’ / Eryngium planum / Phlomis fruticosa

Mulleins combine very well with other plants with grey, downy foliage, such as Stachys byzantina, Salvia argentea, or Phlomis lanata… Also discover Centaurea ragusina, a knapweed with superb silvery foliage and yellow flowers! To enhance this silky, soft aspect, make use of flower spikes of grasses, such as Stipa pennata or Pennisetum… Also plant some Artemisia, such as ‘Powis Castle’. You will obtain a border that plays with rays of sunlight, creating glints on perennial foliage and on grass spikes!

Verbascums with pink or apricot flowers can be used in a romantic or cottage garden. They help create a vintage style. Try the ‘Southern Charm’ variety, and plant it with old-fashioned roses, oriental poppies, nepetas and gypsophilas… Favour pastel shades and soft, warm tones: orange, purple, pink, pale yellow… You can also plant them alongside mauve flower spikes of Phlomis tuberosa ‘Amazone’

Mulleins can also fit into a romantic-style garden! A pairing with Verbascum ‘Rosie’, Delphinium and achilleas / Verbascum ‘Jackie in Pink’ (photo David J. Stang) / Digitalis purpurea / Achillea ‘Apple Blossom’

Mulleins can be included in a colourful mixed border, alongside rudbeckias, echinaceas, achilleas, roses and alchemillas. You will achieve a lovely visual effect by adding some other plants with upright flower spikes to answer the verbascums, as an echo: foxgloves, delphiniums…

With its many properties, Verbascum thapsus can easily be included in a medicinal herb garden. Finally, you can also plant mullein in the vegetable garden, as it attracts a bug (Campylomma verbasci) that feeds on aphids… It is therefore a good companion plant for controlling them.

Did you know?

• Medicinal plant

Verbascum thapsus is a plant effective against sore throat, cough and inflammations of the breathing system. It is a soothing, emollient, mucilaginous plant. It can be consumed as a decoction or an infusion, after being carefully filtered (to remove hairs that can be irritating). Cough syrup can be made using the flowers.