About
Silphium laciniatum, the compass plant, is a large, upright, hairy, aromatic perennial to 3 m producing deeply divided, fern-like, hairy leaves to 50 cm long and narrow sprays of bright-yellow, daisy-like flowers to 12 cm across in late summer and early autumn. The basal leaves orient north-south, giving the plant its common name. A bold and rewarding prairie perennial for a large, sunny, well-drained border.
About the genus
Silphium are robust herbaceous perennials with tall stems bearing simple, aromatic leaves and loose clusters of large, yellow, daisy-like flowers in summer and early autumn. Bold and rewarding plants for a large, sunny, well-drained border or prairie planting.
Growing conditions
SunlightFull sun, Partial shade
Soil typeClay, Loam
Soil pHAlkaline, Neutral
Soil moistureMoist but well-drained
AspectSouth-facing, West-facing
ExposureExposed, Sheltered
UK hardinessH7
Plant details
Plant typeHerbaceous Perennial
HabitColumnar upright
FoliageDeciduous
Height2.5-4 metres
Spread0.5-1 metres
Time to full height2-5 years
Suggested usesWildlife gardens, Architectural, Cottage and informal garden
Native toE North America
FragranceFoliage
Care notes
CultivationGrow in moderately fertile, moist, deep, neutral to slightly alkaline, heavy soil in full sun or partial shade
PruningCut back after flowering; stems may optionally be left until shortly before new growth begins the following season
PropagationPropagate by seed or division
Pest resistanceGenerally pest-free
Disease resistanceGenerally disease-free