*Verbascum*, mullein: to plant, to grow and to maintain

Description and Botany

The mulleins comprise nearly 360 species of biennial or perennial plants, often hairy or pubescent. They are mainly found in Europe and Asia, but also in North Africa. The greatest diversity of species is found in the Mediterranean region. In France, 13 species are present in the wild, including Verbascum thapsus. They grow particularly in fallow land, meadows, rocky places, and along paths…

The best-known is Verbascum thapsus, also known as White Mullein. It is a biennial: it produces a rosette of leaves in the first year, then a flowering stem in the second. It then dies, but can reseed itself. Sometimes, Verbascum thapsus arrives on its own in gardens, naturally seeding itself… like a very decorative weed that one will appreciate keeping!

The White Mullein, Verbascum thapsus, is a ruderal plant: a pioneer plant that establishes itself on disturbed, fallow, or unstable ground. It is one of the first plants to arrive when the soil is still bare. Mullein easily reseeds itself. The seeds and young seedlings need bare soil to develop, which is why it will not spontaneously settle if there is already a true plant cover.

Verbascum thapsus has many vernacular names: Candle of Our Lady, White Mullein, Saint Fiacre’s Herb, Mullein… In the past, the flowering spikes of Verbascum thapsus were used as torches after being soaked in resin, tallow, or wax, which gives it its name Candle of Our Lady. Etymologically, Verbascum is said to be a deformation of the Latin Barbascum: “bearded”, referring to the stamens that bear filaments covered in hairs. The species name, thapsus, comes from Thapsos, an ancient city in Sicily. The name mullein is thought to come from mol: “soft”, in reference to the foliage of the plant.

Verbascum thapsus: botanical illustration

The mullein belongs to the family Scrophulariaceae (nearly 1,600 species). This family includes Buddleias (butterfly bushes), nemesias, and diascias, plants sometimes cultivated in gardens for their abundant and colourful flowering.

The Verbascum have an upright, very straight habit. They measure between 30 cm for the smallest, and 2 m in height for the largest (Verbascum thapsus, in particular). There are beautiful dwarf varieties, such as ‘Sugar Plum’, well-suited for planting at the front of a border, along the edge, or in a large pot to enhance, for example, a terrace.

The mullein starts by forming a rosette of leaves at ground level, then it produces an upright flowering stem. This stem is robust and thick, giving the plant a rather rigid appearance. In biennials, like Verbascum thapsus, the rosette of leaves is formed in the first year, and the flowering stem appears in the second year. It is the cold of winter that enables the plant to flower the following year! The plant will then disappear after dispersing its seeds.

Around June, the plant produces one or more flowering stem(s) from the centre of the rosette of leaves. The White Mullein, Verbascum thapsus, usually produces a single stem. There are also very different species, such as Verbascum acaule, which does not have a flowering stem! Its flowers appear at the level of the rosette of leaves.

The mullein flowers throughout the summer, generally from June to August – September. The flowering period is long, lasting up to three months. The flowers open gradually, succeeding one another, usually from the bottom of the spike to the top. There are often only a few flowers open at the same time on a flowering stem. Each flower is quite ephemeral, lasting generally only a day in Verbascum thapsus… But there are so many flowers on a spike that they continuously succeed one another, allowing the flowering to continue for a long time!

The mullein bears long, dense spikes or clusters, consisting of a very large number of flowers. They can reach up to a metre in length and are more or less branched. They are little branched in Verbascum thapsus, but very branched in Verbascum olympicum… which gives the plant a really different silhouette!

The flowers have a relatively regular shape, with central symmetry… which is rather rare for a plant in the Scrophulariaceae family! They are cup-shaped, well open to the outside. The flowers generally measure 2 to 4 cm in diameter and have five petals of a very rounded shape. They are fused at the base into a very short tube and are surrounded by five sepals. In the centre, there are five stamens, quite decorative. Sometimes, these bear long coloured hairs on their filaments, as in Verbascum nigrum!

The flowers are mostly yellow or white… but many horticultural varieties have been created, now offering flowers in various colours: pink, mauve, violet, orange, copper, or even red… There is even a Verbascum with blue flowers: ‘Blue Lagoon’! The flowering of this one somewhat resembles the flowering spikes of delphiniums! In Verbascum thapsus, the flowers are yellow, and the stamens are orange.

The flowers of mullein can offer beautiful shades and are generally darker at the centre. They are very contrasted in the mullein ‘Cotswold Queen’! Similarly, at the centre of the flower, the stamens often have beautiful orange or purple colours. The flowers of Verbascum nigrum bear purple-stained stamens!

The mullein is an excellent melliferous plant. Many insects, including bees and hoverflies, come to visit the flowers. You can plant mullein to create a border that is beneficial to insects and biodiversity!

The faded inflorescences persist for a long time on the plant. They remain in place during winter. For aesthetic reasons, you can cut them.

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

The mullein is a plant with a very elegant silhouette, with its large spreading leaves all around the stump, and its tall, vertical flowering spike.

The mullein forms a large rosette of leaves at ground level, which can reach up to 60 cm in width! The rosette of Verbascum thapsus remains in place during winter. The plant is thus decorative throughout the year. Its basal leaves measure between 30 and 50 cm long, while those of horticultural varieties are generally smaller.

The mullein also has cauline leaves, placed alternately on the stem (one after the other), smaller than the basal leaves. Generally, the higher you go up the stem, the smaller the leaves become.

In addition to its flowering, mullein is appreciated for its downy and pubescent foliage. The leaves are simple, entire, and ovate in shape. They are thick, although they remain flexible at the same time. They are covered with a white felt, giving them a velvety texture, very soft. The hairs on the leaves give the plant a more or less silvery hue… The species Verbascum bombyciferum is particularly remarkable for its superb grey colour!

The downy foliage of Verbascum thapsus and that of Verbascum phlomoides

The mullein has a taproot, which anchors it firmly in the ground and allows it to draw water from deep down, making the plant quite drought-resistant.

The fruit of the mullein is a capsule that opens by two valves when ripe. Each mullein plant produces a large number of capsules, each containing hundreds of tiny seeds. Thus, a single plant can easily produce more than 100,000 seeds! Moreover, these remain viable (retaining their seed viability) for several decades!

Verbascum thapsus tends to reseed itself spontaneously if the faded flowering stems are left in place. The seeds germinate on bare soil, in an unoccupied space. They do not move far: if new seedlings appear, they will likely be next to the mother plant.

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

The main varieties of Verbascum

The most popular varieties

Our favourite varieties

Other varieties to discover

Verbascum Pink Domino - Mullein

This is a variety with tender pink flowers, shaded with a deeper pink at the centre. It is ideal alongside roses, for a very romantic garden! It has been awarded the Award of Garden Merit by 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 offers flowering in pastel shades, between tender pink, beige, and apricot... With its very soft and 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 is a dwarf variety that offers abundant flowering, mauve pink, contrasted with purple at the centre of the flower. It can be integrated into a border, at the front of a flowerbed, or planted in a large container placed on a terrace.

• 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 nature! It offers extremely bright golden yellow flowering, and fluffy 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! The flowers are slightly shaded by tender 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 and warm flowering. The flowers are apricot in colour, darker at the centre, and carry superb shades.

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

See the product sheet

Verbascum bombyciferum Polarsommer - Mullein

An original mullein with its heavily woolly leaves, giving the plant a superb silvery hue! It also offers 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 brilliant golden yellow flowering, very contrasted by the centre of the flower which is purplish, very dark!

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

See the product sheet

Planting verbascum

Where to plant?

We advise you to plant the mullein in full sun. This is the most favourable exposure, ensuring abundant flowering. Some varieties also thrive in partial shade, as long as the light is sufficient.

Overall, mullein is a low-maintenance plant, but it is imperative that the substrate is well-draining. It dislikes soils that retain water, particularly heavy and compact soils… Avoid this if your land is particularly clayey! (unless planting in a container or significantly improving drainage). It also prefers calcareous, alkaline soils.

As mullein enjoys dry, poor, stony soils, you can easily install it in a rock garden. It is also ideal for greening slopes.

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

As it is an easy plant that requires little and enjoys stony, even sandy soils, you can use it to green a difficult area to landscape. It is perfect for filling space (as it is very voluminous), even in poor soil!

When to plant?

It is preferable to install the mullein in spring, around April, although planting can also take place in autumn.

How to plant?

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

1. Dig a planting hole. Do not hesitate to add draining materials, such as gravel or coarse sand… You can also plant on a mound to facilitate water drainage.
2. Remove the root ball from its pot and plant your Verbascum. The collar should be level with the soil, or slightly above (to prevent water from pooling at the collar).
3. Replace the soil all around the plant, and firm it down.
4. Water generously.

Maintenance

Mullein requires very little maintenance. It tolerates drought well, even in summer. It generally does not need watering and does not require fertiliser either.

We suggest applying a layer of mulch at the base of your mulleins. This will slow down the growth of weeds.

As they have thick, rigid stems, it is usually not necessary to stake mulleins unless they are planted in particularly rich soil or exposed to strong winds.

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

Mullein is a resilient plant, quite insensitive to diseases and pests. It may occasionally be affected by powdery mildew, a fungal disease characterised by the presence of white spots on the leaves. If you notice it, we recommend removing the affected parts and treating with a sulphur-based solution. It can also happen that the leaves are eaten by caterpillars, particularly by the Mullein Moth (Cucullia verbasci).

Multiplication

The best technique for multiplying mullein is by sowing. It sometimes even self-seeds if you have left the faded flower stems in place.

Sowing

You can sow Verbascum seeds in spring, in April or May. However, horticultural varieties may produce flowers that are slightly different from the original variety. On the other hand, verbascum seeds store 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 a seed tray or container by filling it with potting soil (to which you can add a bit of sand to improve drainage). Water it so that the substrate is well moist.
2. Mix the seeds with sand to distribute them more easily over the potting soil.
3. Scatter them on the surface, but do not cover them!
4. You can gently press them down.
5. Place the tray under a cold frame.

The substrate should remain slightly moist until germination, which will occur in one to two weeks. You can plant them outdoors after the last frosts, or in early autumn.

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

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

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

Associating 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 alongside yarrow, Eryngium, teasels (Dipsacus fullonum), spurge… Add some clumps of grasses, such as Stipa tenuifolia. They can also be combined with Mediterranean plants, like Jerusalem sages (Phlomis fruticosa), lavender, rosemary, grasses, Euphorbia characias…

Mulleins can fit into a dry and mineral garden. A 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 pair very well with other plants that have grey, downy foliage, such as Stachys byzantina, Salvia argentea, or Phlomis lanata… Also discover Centaurea ragusina, a centaury with superb silver foliage and yellow flowers! To enhance this silky and soft aspect, take advantage of the flower spikes of grasses, like Stipa pennata or Pennisetum… Also plant some wormwoods, like Artemisia ‘Powis Castle’. You will create a bed that plays with the sun’s rays, creating reflections on the foliage of the perennials and the spikes of the grasses!

Pink or apricot-flowering mulleins can fit into a romantic or cottage garden. They help create a “vintage” style. Particularly enjoy the variety ‘Southern Charm’, and pair it with old roses, Oriental poppies, catmint and gypsophila… Prefer pastel shades, soft and warm tones: orange, purple, pink, soft yellow… You can also plant them alongside the mauve flower spikes of Phlomis tuberosa ‘Amazone’.

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

Mulleins can integrate into a colourful mixed border, alongside rudbeckias, echinaceas, yarrow, roses and lady’s mantle. You will achieve a beautiful visual effect by installing some other plants with erect flower spikes, to echo the mulleins: foxgloves, delphiniums…

With its numerous properties, Verbascum thapsus can easily fit into a medicinal plant garden. Finally, you can also plant mulleins in the vegetable garden, as they attract a bug (Campylomma verbasci) that eats aphids… So, it is a good companion plant to combat these pests.

Did you know?

• A medicinal plant

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