What hardiness zones is Verbascum olympicum suitable for?

Verbascum olympicum is Olympic mullein (Greek mullein), a biennial (sometimes short-lived monocarpic perennial) forming a silver-white densely woolly basal rosette 12-18 inches (30-45 cm) tall in the first year. In the second year, branched candelabra-like flower spikes rise to 60-96 inches (150-240 cm / 5-8 feet) bearing bright yellow 5-petaled flowers 1 inch (2.5 cm) diameter. Silver-white densely woolly (tomentose) oblong to spatulate basal leaves 12-18 inches (30-45 cm) long. In the figwort family (Scrophulariaceae). The tallest commonly grown Verbascum species. Biennial: forms a basal rosette in year 1, sends up the flowering candelabra in year 2, then dies after setting seed. Self-sows readily — allow one stalk to set seed for replacement plants. Tolerates poor, dry, alkaline, and rocky soils — one of the most drought-tolerant garden biennials. Does not tolerate wet winter soil — crown rot in poorly drained sites is the primary limitation; requires sharp drainage. Native to rocky slopes and dry meadows in Greece, Turkey, and western Asia. Zones 5-9. Deer-resistant. Non-toxic. Full sun. Growth rate is moderate (year 1) to fast (year 2 flowering spike).

Native Range

Native to Europe (Greece, Turkey) and western Asia. Found on rocky slopes and dry meadows in the eastern Mediterranean.

Suggested Uses

Grown in dry gardens, gravel gardens, Mediterranean-style plantings, and naturalized meadows. The tallest Verbascum — candelabra spikes 5-8 feet (150-240 cm). Tolerates poor dry alkaline soil. Self-sows. Deer-resistant. Non-toxic. Biennial — zones 5-9.

How to Identify

Identified by a large silver-white densely woolly basal rosette in year 1 and branched candelabra-like flower spikes 60-96 inches (150-240 cm) with bright yellow flowers in year 2. The densely woolly (tomentose) silver foliage and the branched candelabra form distinguish V. olympicum from V. thapsus (common mullein — single unbranched spike). In Scrophulariaceae.

Appearance

Size & Dimensions

Height5' - 8'

Width/Spread2' - 3'

Reaches mature size in approximately 3 years

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~5 weeks

Summer

Summer (June-August). Bright yellow 5-petaled flowers 1 inch (2.5 cm) on branched candelabra-like spikes. 5 weeks of bloom. Bee-pollinated. Second-year bloom only (biennial).

Detailed Descriptions

Flower Description

Bright yellow, 5-petaled, 1 inch (2.5 cm) diameter, clustered on branched candelabra-like flower spikes

Foliage Description

Silver-white, densely woolly (tomentose); basal rosette leaves 12-18 inches (30-45 cm) long, oblong to spatulate

Growing Conditions

Sun Requirements

Full Sun

Requires 6-12 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range6.5 - 8.0(Alkaline)

357912

Soil Types

sand chalk loam rocky

Drainagewell drained

Water & Climate

Water Needs

Low

Frost Tolerance

hardy

Time to Maturity

2-3 years from seed to flower (biennial: rosette year 1, flowers year 2)

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Full sun (6+ hours). Well-drained to dry soil pH 6.5-8.0 — tolerates poor, alkaline, and rocky soils. No fertilization needed. Crown rot in wet winter soil — requires sharp drainage. Biennial: dies after flowering and seeding. Self-sows. Deer-resistant. Drought-tolerant. Non-toxic. Zones 5-9.

Pruning

Cut the main flower stalk after bloom to encourage lateral branching. Leave one stalk to set seed for self-sowing replacement plants. Remove the spent biennial plant in late fall or early spring. Cut back the dead rosette in early spring before new seedlings emerge.

Pruning Schedule

early spring

Maintenance Level

very low

⚠️ Toxicity Warning

Non-toxic