Great mullein

Great mullein: how do you recognise it?

Habit

Biennial: a rosette in the first year, a straight, usually unbranched flower candle up to 1.8 m in the second, 50 cm wide.

Leaves

Large, lance-shaped to oblong, silver-grey and densely felted; the leaf bases run down the stem.

Flower

Yellow flowers with five petals, packed close on the stem, from June to September; they open one at a time.

Roots

Deep taproot that withstands drought well; move it only while it is small.

Seed

Very many tiny seeds in capsules, ripening in late summer and autumn.

Flowering: June–September · Sowing: April–June · Plants: September–October

Why grow it?

• Bold, silver-grey rosettes in the first year that stay attractive in winter.
• A straight yellow candle up to 1.8 m in the second year, from June to September.
• A native plant that attracts bees and bumblebees with its pollen.
• Thrives on the driest, poorest soil where little else grows.
• No work: it self-sows and manages without water or feed.

Great mullein: where does it grow best?

• Full sun: the warmer and drier, the better.
• Well-drained, poor sandy or loamy soil, neutral to chalky.
• Dry to normal; it tolerates drought very well, but not the wetness of a wet winter.
• Plant 50 cm apart, in a spot where you do not mind its seedlings.

Light

Sun

Soil type

Sand or loam

Acidity

Not fussy

Moisture

Dry

Size

1.8 m tall, 0.5 m wide

Hardiness

Hardy (to -25 °C)

Goes well with

• Wild marjoram: A scented, low plant for the same dry, sunny soil.
• Viper’s bugloss: Blue flowers and a bee plant beside the yellow candles.
• Wild carrot: White umbels in the same poor vegetation.
• Biting stonecrop: A low ground cover in the same dry soil.
• Globe thistle: Blue globes beside the yellow candles.

Great mullein: when and how to plant it?

Plant in September–October.

1. Sow outdoors in April–June, in place or in a seedbed, in full sun.
2. Scatter the very fine seed on loose soil and only press it in: it germinates in light.
3. Keep the seedbed moist until the seedlings appear and thin them to 40–50 cm.
4. Move young rosettes in September–October; keep the taproot as intact as possible.
5. Plant at the same depth as before; do not add manure or compost.
6. Water once after planting; after that it looks after itself.

Care

Water

In the first year only in long dry spells; after that not at all.

Feeding

Avoid: on rich soil it grows floppy and falls over more easily.

Support

Usually not needed; in windy spots a sturdy stake may help.

Deadheading

Leave the candle as winter interest and for seed, or cut the spike to limit self-sowing.

Maintenance

Remove unwanted seedlings in spring; they pull out easily while they are small.

Tip: Sow in place on dry soil and leave seedlings where they come up. It needs no feed: the poorer the soil, the sturdier it grows.

Great mullein: when to prune it?

When: It is not pruned; cut the spikes only to limit self-sowing, or tidy it away after flowering.

How:

• Cut the faded spike before the seed ripens if you do not want seedlings.
• Leave the candle as winter interest and as a seed source for birds and insects.
• Remove the dead plant in late winter or spring.

Caution: It self-sows freely and its seed stays viable in the soil for decades. Cut the spikes before the seed ripens if you do not want that.

Pruning calendar and basic rules

Propagation

Seed

In April–June outdoors, in place or in a seedbed, in full sun. Scatter the seed on the soil and press in; it germinates in light.

Self-sown seedlings

Let a few spikes set seed; the young plants come up by themselves. Move young rosettes in September–October or leave them where they appear.

Great mullein: how does it get through the winter?

Hardy to −25 °C.

• Fully hardy, to about −25 °C. The rosette stays green or silver-grey.
• The only real danger is wet soil in winter: the rosette may rot away. Make sure the soil is well drained.
• In the second year the plant dies after flowering; the seed gives new plants.

Diseases and pests

• Caterpillars: Moth caterpillars chew the leaves, especially in May–June. Pick them off or leave them: the plant survives.
• Rot: The rosette rots in wet, cold winters. Make sure the soil is well drained and avoid places that are too wet.
• Slugs: Young seedlings are eaten. Sow slightly thicker and thin later.
• No flowers in the first year: That is normal: it is biennial. The flowering spike comes in the second year.
• Unwanted seedlings: Pull them out while they are small; the taproot soon goes deep.

Through the year

• April: Sow outdoors, in place or in a seedbed.
• May: Finish sowing. Thin seedlings.
• June: First flowers on second-year plants. Sowing still possible.
• July: Full flower. Bees and bumblebees visit the spike.
• August: Flowering and seeding. Cut spikes if you do not want seed.
• September: Move young rosettes. Collect seed.
• October: Move young rosettes. Clear dead plants.
• November: Rosettes stay in place; do nothing.
• December: Rest.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Did you know?

• According to tradition, the dried stems were once used as torches, which fits names such as ‘hag taper’ and the Dutch koningskaars (king’s candle).
• After flowering the plant dies, but the seed can lie dormant in the soil for decades and germinate only when the ground is turned over.
• The dense, felted hairs protect the leaves against evaporation and sun.