Murdock's Thistle
Cirsium tweedyi
- Native to:
- United States
iNaturalist: © michaelthaibinh (iNaturalist #305960661)






Taxonomy
- Division:
- Magnoliophyta | - Flowering plants
- Family:
- Asteraceae
- Genus:
- Cirsium
- Species:
- Cirsium tweedyi
- USDA Symbol:
- CIMU2
Growth Characteristics
- Life Cycle:
- Biennial | Perennial
- Growth Habit:
- Forb/herb
- Height:
- 120 cm
- Light Requirements:
- Full Sun
- Drought Tolerance:
- Medium
- Bloom Months:
- jun,jul,aug
- Bloom Colors:
- white, pink, lavender
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)
Garden & Ecology Notes
- Wildlife Value:
- bees, butterflies, birds
- Deer Resistant:
- Yes
- Fire Ecology:
- Fire adapted — tolerates or benefits from fire
- Fire Notes:
- Resprouts from rootstock following fire; often increases in abundance in early post-fire years.
Soil Requirements
- Soil Type:
- well-drained, sandy or rocky soil
- pH:
- 6.0 - 7.5 (slightly acidic to neutral)
- Drainage:
- excellent drainage required
- Moisture:
- dry to moderate
- Notes:
- native to open, rocky slopes and meadows
Propagation & Germination
- Stratification:
- Cold/moist stratification required — 30–60 days
- Germination Time:
- 14–30 days
- Notes:
- Seeds germinate best with light exposure and cool temperatures after cold stratification.
The above propagation data sourced from Claude AI