Roughstem Rosinweed
Silphium radula
Also known as: Reverchon's Rosinweed
- Native to:
- United States
Eric Hunt
Taxonomy
- Division:
- Magnoliophyta | - Flowering plants
- Family:
- Asteraceae
- Genus:
- Silphium
- Species:
- Silphium radula
- USDA Symbol:
- SIRA2
Growth Characteristics
- Life Cycle:
- Perennial
- Growth Habit:
- Forb/herb
- Height:
- 150 cm
- Light Requirements:
- Full Sun
- Drought Tolerance:
- Medium
- Bloom Months:
- jun,jul,aug,sep
- Bloom Colors:
- yellow
Wildlife Benefits
- Bees:
- ★☆☆☆☆ Documented bee visitation (GBIF)
- Butterflies & Moths:
- ★☆☆☆☆ Documented Lepidoptera association (GBIF)
Keystone Species Ranking
- Pollen Specialist Bee Keystone:
- ★★☆☆☆ Native pollen specialist bee species supported by this genus (NWF)
Reported Fauna Sightings
Bees: American bumble (Bombus pensylvanicus), ⚠️Western honey bee (Apis mellifera), Xylocopa strandi
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. Fire promotes flowering and reduces competition.
Soil Requirements
- Soil Type:
- sandy, well-drained, nutrient-poor soil
- pH:
- 6.0 - 7.5 (slightly acidic to neutral)
- Drainage:
- excellent drainage required
- Moisture:
- dry to moderate
- Notes:
- Prefers open, sunny habitats like prairies.
Propagation & Germination
- Stratification:
- Cold/moist stratification required — 60–90 days
- Germination Time:
- 14–30 days
- Notes:
- Cold stratification improves germination rates. Seeds may be sown in fall for natural stratification.
The above propagation data sourced from Claude AI