Tansy Rosinweed

Silphium pinnatifidum

Native to:
United States

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Taxonomy

Division:
Magnoliophyta | - Flowering plants
Family:
Asteraceae
Genus:
Silphium
Species:
Silphium pinnatifidum
USDA Symbol:
SIPI2

Growth Characteristics

Life Cycle:
Perennial
Growth Habit:
Forb/herb
Height:
180 cm
Light Requirements:
Full Sun
Drought Tolerance:
Medium
Bloom Months:
jul,aug,sep
Bloom Colors:
yellow

Wildlife Benefits

Bees:
★☆☆☆☆ Documented bee visitation (GBIF)
Butterflies & Moths:
★☆☆☆☆ Documented Lepidoptera association (GBIF)
Caterpillars:
★☆☆☆☆ Recorded caterpillar host plant (HOSTS Database)

Keystone Species Ranking

Pollen Specialist Bee Keystone:
★★☆☆☆ Native pollen specialist bee species supported by this genus (NWF)

Host Plant for Caterpillars

silphius borer moth (Papaipema silphii)

Garden & Ecology Notes

Wildlife Value:
bees, butterflies, birds
Deer Resistant:
Yes
Fire Ecology:
Fire adapted — tolerates or benefits from fire
Fire Notes:
Resprouts vigorously from deep taproot following fire; historically part of fire-maintained prairies and barrens.

Soil Requirements

Soil Type:
rich, well-drained loamy soil
pH:
5.5 - 7.0 (slightly acidic to neutral)
Drainage:
excellent drainage required
Moisture:
dry to moderate
Notes:
prefers open, sunny habitats

Propagation & Germination

Stratification:
Cold/moist stratification required — 60–90 days
Germination Time:
14–30 days
Notes:
Cold stratification improves germination rates. Surface sow or lightly cover seeds.

The above propagation data sourced from Claude AI