How to Grow and Care for Mullein

Common mullein (Verbascum thapsus) grows in pastures and meadows that have been neglected, on the side of the road and the edges of woods, along fence rows, in vacant lots and industrial areas. In the first year, plants grow low to the ground, bearing rosettes of hairy leaves. Gray-green in color, oblong to lanceolate, each soft leaf measures 4 to 12 inches long and 1 to 5 inches wide. This herbaceous biennial or short-lived perennial has a deep taproot. For the plant to come back and flower in the spring of its second year, it needs to be exposed to cold temperatures in a process known as vernalization.

Flowers attract flies, butterflies, short- and long-tongued bees, and other insects.

Mullein Plant Care

This plant grows in the wild in the United States and Canada where the growing season lasts 140 days or more and there is enough rainfall on dry, sandy soils. Here are the main care requirements for growing mullein:

• Use well draining, poor to average soil that’s slightly alkaline.
• Plant mullein in full sun. Space taller types 3 feet apart, shorter varieties 1 foot apart.
• Keep soil moist when growing from seed or when flowering, otherwise, mullein is drought tolerant.
• Feed with a slow release 10-10-10 fertilizer.
  

Warning

Common mullein is considered invasive in 20 states, largely in the west. Mullein produces a large amount of seeds that can remain viable for decades, and once established, it can crowd out native species and be difficult to remove.

Light

Mullein thrives in full sun. Plant them in a dry, warm spot near walls or large trees to protect them from wind.

Soil

Grow mullein in just about any type of soil, preferably soil that is dry and slightly alkaline. The plant will also adapt to poor, calcareous soil. Being so adaptable, it can spread quickly, creating dense patches even faster than some native plants.

Water

Keep the soil moist when growing mullein from seed. While the plant doesn't need much moisture, water more often as it starts to flower.

Temperature and Humidity

Common mullein is a tough plant that can withstand extremes at either end of the temperature spectrum. It is hardy down to -25 degrees F and will thrive throughout a hot summer if watered occasionally in the absence of rain. It is not finicky about humidity levels.

Fertilizer

Mullein can grow faster and produce more flowers when fed with a low release 10-10-10 fertilizer. For the amount to use, follow product label instructions.

Types of Mullein

More than 300 varieties are native to Europe, West and Central Asia, and North Africa. Of the Scrophulariaceae snapdragon family, their long terminal flower spikes are reminiscent of snapdragon flowers. Common types spread quickly and can be controlled in their first year by weeding out young rosettes, but hybrid types (called ornamental mullein) tend to be less invasive and better for gardens. Flowers come in white, pink, lavender, purple, and yellow. Here are a few types of mullein to consider:

• 'Moth mullein' (V. blattaria): Two to five feet tall with white or yellow flowers
• 'Olympic (or Greek) mullein' (V. olympicum): Five-foot branching stalks of bright yellow flowers
• 'Purple mullein' (V. phoeniceum):A short-lived variety that reaches a compact 3 feet tall and produces dark purple or violet flowers
• 'Nettle-leaf mullein' (V. chaixii):A compact variety that grows 2 to 3 feet tall; ithas white blooms with purple centers that are long lasting
  

Propagating Mullein

Propagate mullein from seeds and cuttings. Either buy seeds or collect seeds from plants as soon as the fruits are borne from flowers.

Mullein, with its deep taproot, can be also be propagated through root cuttings when the plant is dormant in late fall to early spring. Here’s how:

1. You will need a shovel, sharp knife or pruners, potting soil, and a starter pot.
2. With a shovel, dig up a mullein plant around it’s base to expose its roots.
3. Choose a root near the center crown of the plant, and with a sharp knife, cut across the root.
4. For deep vertical root cuttings, trim down from the top where it was cut from at the crown so the root cutting is a few inches long.
5. Plant in well draining, potting soil with with top that was cut near the crown right side up.
6. Keep in full sun with moist soil and transplant to the garden once a true set of leaves start to form.

How to Grow Mullein From Seed

Seeds usually fall just a few feet away from the parent plant, blown down by the wind or shaken down by an animal. None are known to disperse long-distance. Seeds can remain alive and viable for decades in the soil. Seeds that are on the surface or just below it will have enough light to germinate. So the more the soil is disturbed, the more likely seeds will emerge and sprout. That's why these plants are so invasive in areas with poor to average soil disturbed by logging, fire, and storms.

Drought-tolerant and prolific seed producers (a whopping 100,000‑240,000 seeds per plant), the plant grows quite easily from seed. Here’s how:

1. Start seeds indoors in early spring or outdoors in late spring.
2. Scatter them on the top of rich potting soil or sow a pinch of seeds 18 inches apart and just 1/16 inch deep in well-drained soil. Look for sprouts two weeks later.
3. Once indoor plants have grown a true set of leaves, divide and transplant the seedlings into a bigger container or harden them off and transplant them into the garden. For plants seeded directly in the garden, thin seedlings to at least 12 inches apart.

Because these plants readily self-sow, remove unwanted plants to keep your garden from being overrun with mullein.

Overwintering

Mullein is winter hardy but for extra root protection, mulch before the projected frost date with twigs, leaves, and bark.

Common Pests and Plant Diseases

Mullein is resistant to pests. Aphids are only rarely a problem. Avoid planting mullein in heavily compacted soil as such poorly draining soil can encourage root rot.

How to Get Mullein to Bloom

Bloom Months

Mullein typically blooms between June and September, depending on the USDA zone.

How Long Does Mullein Bloom?

This plant can bloom for about six weeks during the summer.

What Do Mullein's Flowers Look and Smell Like?

Flower stalks grow quite tall (anywhere from two to seven feet), bearing small, yellow (rarely white), five-petaled flowers grouped closely on a leafy spike. Blooming a few at a time from June to September, they mature from the bottom to the top of the spike in spirals. In addition to its especially soft, felt-like foliage, another characteristic that makes this plant unique is that each individual bloom opens before sunrise and closes by mid-afternoon. The small yellow flowers smell like honey.

Deadheading Mullein Flowers

This plant can bloom for about six weeks during the summer, to keep mullein blooming, deadhead the spent flowers. Deadheading will also make the plant look neater, keep it healthy, and prevent seed formation. Cut the stalk at its base once it’s done flowering.

From: thespruce