
Image: AI generated
Stalked Mullein Plant Care
Verbascum wilhelmsianum K.Koch
Updated · Sources · How we source care data
With its striking silvery-green leaves covered in soft hairs, Verbascum wilhelmsianum originates from the rocky cliffs of Turkey. This unique plant is highly sought after by collectors for its rare and unusual foliage, adding a touch of texture and interest to any garden or landscape.
Every 7–14 days
Full sun to part shade
50–80°F
40–70%
At a glance
How do you care for Stalked Mullein?
Plant Stalked Mullein in full sun to part shade (USDA zones 12a) and water a young shrub every 7–14 days until it is established. It tolerates temperatures of 50–80°F (10–27°C). Fertilize it every 6 months during the growing season.
What Is the Stalked Mullein?
Stalked Mullein (Verbascum wilhelmsianum) belongs to the Scrophulariaceae family within the Verbascum genus. Stalked Mullein is native to Mediterranean region, Italy, Greece. Stalked Mullein is also known as Wilhelms' Mullein.
Stalked Mullein displays a tall spires of flowers growth habit, reaching up to 4 ft tall with a spread of approximately 2 ft. Stalked Mullein produces large, showy spikes of yellow, pink, or purple flowers.
Leaf size: approximately 6 inches.
How Often Should You Water a Stalked Mullein?
Water a young or newly planted Stalked Mullein every 7–14 days, soaking the whole root zone, until it is established — usually one to two growing seasons. Established shrubs mainly need water during long dry spells. In a container, water whenever the top few centimetres of soil are dry.
Watering Frequency
Every 7–14 days
Until established; then in dry spells
What Light Does the Stalked Mullein Need?
Stalked Mullein thrives in full sun to part shade.
Light Requirement
Full sun to part shade
What Temperature and Humidity Does the Stalked Mullein Prefer?
Verbascum wilhelmsianum tolerates temperatures of 50–80°F. Stalked Mullein prefers humidity levels of 40–70%.
Temperature
50–80°F
Humidity
40–70%
What Soil Mix Works Best for a Stalked Mullein?
Well-draining sandy loam with added compost for nutrients. Good drainage is essential for Stalked Mullein to prevent waterlogging, which leads to root rot and fungal issues.
How Often Should You Fertilize a Stalked Mullein?
Feed Stalked Mullein every 6 months during the growing season with a balanced, slow-release fertilizer at the rate on the label. Established shrubs in good soil often need little extra feeding, so let weak growth or pale foliage guide you.
Stop feeding by late summer so new growth can harden before winter.
Fertilizing
Every 6 months
During the growing season
The PlantoScan app can remind you when to water and when to fertilize each plant.
Where Should You Plant a Stalked Mullein?
Choose a spot with full sun to part shade and well-draining sandy loam with added compost for nutrients. Avoid low spots where water collects after rain.
Stalked Mullein is suited to USDA Zone 12a.
Plant container-grown or balled-and-burlapped shrubs in spring or early autumn, setting the root flare at soil level, and water well after planting.
How Far Apart Should You Plant a Stalked Mullein?
Stalked Mullein can spread to about 2 ft (0.6 m) and reach about 4 ft (1 m) tall. Space plants about 2 ft (0.6 m) apart so mature crowns don't crowd each other, and plant at least half that distance from buildings, fences and paths.
Planning a row or hedge? Try the plant spacing calculator.
How Do You Prune a Stalked Mullein?
Prune Stalked Mullein while it is dormant in late winter: first remove dead, damaged and crossing branches, then thin lightly for shape.
If it flowers in spring, prune right after flowering instead so you don't remove next year's buds. Never take off more than about a quarter of the shrub in one year.
How Do You Care for a Stalked Mullein in Winter?
Stalked Mullein is frost-tender (hardy to USDA zone 12). In colder areas grow it in a container and move it to a bright, frost-free place before the first frost.
How Do You Propagate a Stalked Mullein?
Stalked Mullein can be propagated through seeds, division of offsets. Similar propagation techniques also apply to bombyciferum mullein plant care, which shares the same genus.
Is the Stalked Mullein Toxic to Pets and Children?
Pet safety not verified
The ASPCA does not list Stalked Mullein, so we can't confirm whether it is safe for cats and dogs. Keep pets from chewing it as a precaution.
This is a general caution, not veterinary or medical advice. If your pet ate a plant, contact your vet or animal poison control.
See all plants toxic to cats and plants toxic to dogs.
What Pests and Diseases Affect the Stalked Mullein?
Stalked Mullein is susceptible to aphids, slugs, snails. Inspect the foliage regularly, especially along leaf undersides and stems. Treat infestations promptly with insecticidal soap or neem oil to prevent spread.
Yellow leaves, brown tips or drooping? See common plant problems and how to fix them.
What USDA Hardiness Zone Does the Stalked Mullein Need?
Stalked Mullein grows outdoors in USDA Zone 12a. It survives winters down to planting zone 12a. Stalked Mullein is native to Mediterranean region, Italy, Greece. In cooler regions, grow Stalked Mullein as a houseplant or bring it indoors before the first frost.
Hardiness Zone
Zone 12a
Keep exploring plants
Stalked Mullein is one of many species covered in the complete plant care and identification guide, which groups plants by genus, attribute, and popularity.
It belongs to the Verbascum genus — compare its care with other Verbascum species on PlantoScan.
Verbascum is part of the Scrophulariaceae plant family — browse all Scrophulariaceae genera and species.
Stalked Mullein thrives in bright light and direct sun — see other bright-light plants.
More Verbascum Species
Other Verbascum species in PlantoScan's care catalogue share similar watering, light, and soil preferences:
Sources
- Scientific name & taxonomy: Verbascum wilhelmsianum K.Koch, family Scrophulariaceae (first published in Linnaea 22: 724 (1849)) — World Flora Online record, IPNI name record.
- Pet toxicity: Pet safety not verified: the ASPCA does not list Stalked Mullein, so we can't confirm whether it is safe for cats and dogs. Checked against the ASPCA plant list; any other toxicity note on this page comes from PlantoScan's plant database.
- Photo: AI-generated illustration (labelled on the image).
- Hardiness zone: USDA Zone 12a, calculated from the plant's minimum temperature.
- Care values(watering, light, temperature, humidity, soil, fertilizing): PlantoScan's plant database, filtered by automatic plausibility checks — values that fail them are hidden. How we source and check plant data.
Spotted a mistake? Email info@upvision.media with the page link — we check and correct reported errors.
