Marrubium Species, Horehound
Marrubiumcylleneum

Synonym:Marrubium candidissimum

Synonym:Marrubium velutinum subsp. cylleneum

Category
Herbs

Water Requirements
Average Water Needs; Water regularly; do not overwater

Sun Exposure
Full Sun

Foliage
Grown for foliage
Herbaceous

Foliage Color

Height
24-36 in. (60-90 cm)

Spacing
15-18 in. (38-45 cm)

Hardiness
USDA Zone 4a: to -34.4 °C (-30 °F)
USDA Zone 4b: to -31.6 °C (-25 °F)
USDA Zone 5a: to -28.8 °C (-20 °F)
USDA Zone 5b: to -26.1 °C (-15 °F)
USDA Zone 6a: to -23.3 °C (-10 °F)
USDA Zone 6b: to -20.5 °C (-5 °F)
USDA Zone 7a: to -17.7 °C (0 °F)
USDA Zone 7b: to -14.9 °C (5 °F)
USDA Zone 8a: to -12.2 °C (10 °F)
USDA Zone 8b: to -9.4 °C (15 °F)
USDA Zone 9a: to -6.6 °C (20 °F)
USDA Zone 9b: to -3.8 °C (25 °F)

Where to Grow

Danger
N/A

Bloom Color
White/Near White

Bloom Characteristics

Bloom Size

Bloom Time
Mid Summer

Other details

Soil pH requirements
6.1 to 6.5 (mildly acidic)
6.6 to 7.5 (neutral)
7.6 to 7.8 (mildly alkaline)
7.9 to 8.5 (alkaline)

Patent Information
Non-patented

Propagation Methods
By dividing the rootball
From herbaceous stem cuttings
Allow cut surface to callous over before planting
From seed; direct sow outdoors in fall
From seed; direct sow after last frost
By simple layering
By serpentine layering

Seed Collecting
Bag seedheads to capture ripening seed
Allow seedheads to dry on plants; remove and collect seeds
Properly cleaned, seed can be successfully stored