Taxonomy

Division:

Magnoliophyta | - Flowering plants

Family:

Asteraceae

Genus:

Cirsium

Species:

Cirsium rydbergii

USDA Symbol:

CIRY

Growth Characteristics

Life Cycle:

Perennial

Growth Habit:

Forb/herb

Height:

150 cm

Light Requirements:

Full Sun

Drought Tolerance:

Low

Bloom Months:

jul,aug,sep

Bloom Colors:

white, pink, purple

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 root crown following fire; typical of montane meadow species in fire-prone ecosystems.

Soil Requirements

Soil Type:

moist, well-drained loamy soil

pH:

6.0 - 7.5 (slightly acidic to neutral)

Drainage:

good drainage required

Moisture:

consistently moist

Notes:

prefers riparian or wetland areas

Propagation & Germination

Stratification:

Cold/moist stratification required — 30–60 days

Germination Time:

14–28 days

Notes:

Light may aid germination. Seeds germinate best at cool temperatures after cold stratification.

The above propagation data sourced from Claude AI