White Thistle
Cirsium hookerianum
- Native to:
- Canada, United States
iNaturalist: © bevramey (iNaturalist #65614473)
Taxonomy
- Division:
- Magnoliophyta | - Flowering plants
- Family:
- Asteraceae
- Genus:
- Cirsium
- Species:
- Cirsium hookerianum
- USDA Symbol:
- CIHO
Growth Characteristics
- Life Cycle:
- Perennial
- Growth Habit:
- Forb/herb
- Height:
- 100 cm
- Light Requirements:
- Full Sun
- Drought Tolerance:
- Medium
- Bloom Months:
- jun,jul,aug
- Bloom Colors:
- white, cream
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: Brown-belted bumble bee (Bombus griseocollis), Hunt's bumble bee (Bombus huntii), White-shouldered bumble bee (Bombus appositus), Yellow bumble bee (Bombus fervidus)
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; common in post-fire meadow communities.
Soil Requirements
- Soil Type:
- moist, well-drained loamy soil
- pH:
- 5.5 - 7.0 (slightly acidic to neutral)
- Drainage:
- good drainage required
- Moisture:
- consistently moist
- Notes:
- prefers open, grassy areas in native range
Propagation & Germination
- Stratification:
- Cold/moist stratification required — 30–60 days
- Germination Time:
- 14–30 days
- Notes:
- Light may enhance germination. Sow on surface or cover lightly.
The above propagation data sourced from Claude AI
Pre-treatment: 5 month outdoor cold, moist stratification
Establishment: Collect mature achenes in mid September when they turn grey and are easily separated from the receptacle. Seeds are collected in paper bags and kept in a well ventilated drying shed prior to cleaning.
Source: npn.rngr.net
ORGHPS Germination Guide: Sow @ 20C. Germinates within 3 months.