Silphium Species, Roughstem Rosinweed, Showy Rosinweed
Silphiumradula

Synonym:Silphium asperrimum

Synonym:Silphium dentatum var. gatesii

Synonym:Silphium gatesii

Category
Perennials

Water Requirements

Sun Exposure
Full Sun

Foliage

Foliage Color

Height
36-48 in. (90-120 cm)

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

Hardiness
USDA Zone 3a: to -39.9 °C (-40 °F)
USDA Zone 3b: to -37.2 °C (-35 °F)
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

Bloom Color
Bright Yellow

Bloom Characteristics

Bloom Size

Bloom Time
Mid Summer
Late Summer/Early Fall

Other details

Soil pH requirements

Patent Information

Propagation Methods

Seed Collecting