Suisun Thistle
Cirsium hydrophilum
- Native to:
- United States
iNaturalist: © morganstickrod (iNaturalist #122395507)






Taxonomy
- Division:
- Magnoliophyta | - Flowering plants
- Family:
- Asteraceae
- Genus:
- Cirsium
- Species:
- Cirsium hydrophilum
- USDA Symbol:
- CIHY
Growth Characteristics
- Life Cycle:
- Biennial | Perennial
- Growth Habit:
- Forb/herb
- Height:
- 200 cm
- Light Requirements:
- Full Sun
- Drought Tolerance:
- Low
- Bloom Months:
- jun,jul,aug,sep
- Bloom Colors:
- pink, purple, white
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
Mylitta crescent (Phyciodes mylitta), Painted Lady (Vanessa cardui)
Garden & Ecology Notes
- Wildlife Value:
- bees, butterflies, birds
- Salt Tolerant:
- Yes
Soil Requirements
- Soil Type:
- rich, moisture-retentive clay loam
- pH:
- 6.0 - 7.5 (slightly acidic to neutral)
- Drainage:
- tolerates poor drainage
- Moisture:
- consistently moist
- Notes:
- native to marshy areas and wetlands
Propagation & Germination
- Stratification:
- Cold/moist stratification required — 30–90 days
- Germination Time:
- 14–30 days
- Notes:
- Seeds germinate best with light exposure and consistent moisture.
The above propagation data sourced from Claude AI