About
A very tall herbaceous perennial, to 4m, with a basal rosette of very large, oblong to heart-shaped leaves. Sturdy, upright, branching stems support masses of yellow, daisy-like flowers from mid-summer to mid-autumn.
About the genus
Silphium are robust herbaceous perennials with tall stems bearing simple leaves, aromatic when bruised, and loose clusters of yellow, daisy-like flowers in summer and early autumn
Growing conditions
SunlightFull sun, Partial shade
Soil typeClay, Loam
Soil pHAlkaline, Neutral
Soil moistureMoist but well-drained, Well-drained
AspectSouth-facing, West-facing, East-facing
ExposureExposed, Sheltered
UK hardinessH7
Plant details
Plant typeHerbaceous Perennial
HabitBushy
FoliageDeciduous
Height2.5-4 metres
Spread0.5-1 metres
Time to full height2-5 years
Suggested usesCottage and informal garden, Architectural, Prairie planting
Native toE North America
FragranceFoliage
Care notes
CultivationGrow in moist, deep, neutral to slightly alkaline soil in full sun or partial shade; best in heavy soil
PruningMay be cut back after flowering, or leave architectural stems until shortly before new growth begins the following season
PropagationPropagate by seed or division
Pest resistanceGenerally pest-free
Disease resistanceGenerally disease-free