Suisun Thistle

Cirsium hydrophilum

Native to:
United States

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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