Field Thistle
Cirsium discolor
- Native to:
- Canada, United States
iNaturalist: © farah58 (iNaturalist #135663272)
Taxonomy
- Division:
- Magnoliophyta | - Flowering plants
- Family:
- Asteraceae
- Genus:
- Cirsium
- Species:
- Cirsium discolor
- USDA Symbol:
- CIDI
Growth Characteristics
- Life Cycle:
- Biennial | Perennial
- Growth Habit:
- Forb/herb
- Height:
- 200 cm
- Light Requirements:
- Full Sun
- Drought Tolerance:
- Medium
- Bloom Months:
- jun,jul,aug,sep,oct
- 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
Painted Lady (Vanessa cardui)
Reported Fauna Sightings
Bees: eastern thistle longhorn bee (Melissodes desponsus), Half-black bumble bee (Bombus vagans), Lemon cuckoo (Bombus citrinus), Northern amber (Bombus borealis), 🛑Rusty-patched bumble (Bombus affinis), Two-spotted bumble (Bombus bimaculatus), ⚠️Western honey bee (Apis mellifera), Xenoglossa pruinosa, Yellow bumble (Bombus fervidus) Hummingbirds: Ruby-throated Hummingbird (Archilochus colubris) Butterflies:Atalopedes Scudder, Black Swallowtail (Papilio polyxenes), Cloudless Sulphur (Phoebis sennae), Delaware Skipper (Anatrytone logan), Eastern Giant (Heraclides cresphontes), Eastern Tiger Swallowtail (Pterourus glaucus), Eastern Tiger Swallowtail (Papilio glaucus), Great Spangled (Argynnis cybele), Julia butterfly (Dione vanillae), ⚠️Monarch butterfly (Danaus plexippus), Painted Lady (Vanessa cardui), Peck's skipper (Polites peckius), Pipevine Swallowtail (Battus philenor), Silver-spotted Skipper (Epargyreus clarus), Spicebush Swallowtail (Papilio troilus), Zabulon Skipper (Lon zabulon)
Garden & Ecology Notes
- Wildlife Value:
- bees, butterflies, goldfinches, hummingbirds
- Deer Resistant:
- Yes
- Fire Ecology:
- Fire adapted — tolerates or benefits from fire
- Fire Notes:
- Resprouts from root crown after fire. Often increases in abundance following prescribed burns in prairie ecosystems.
Soil Requirements
- Soil Type:
- rich, well-drained loamy soil
- pH:
- 5.5 - 7.0 (slightly acidic to neutral)
- Drainage:
- excellent drainage required
- Moisture:
- dry to moderate
- Notes:
- prefers open fields and prairies
Propagation & Germination
- Stratification:
- Cold/moist stratification required — 30–60 days
- Germination Time:
- 14–30 days
- Notes:
- Seeds germinate readily after cold stratification. Light may enhance germination.
The above propagation data sourced from Claude AI
Pre-treatment: Cold-moist stratification for 30 days at 1–5°C (34–41°F).
Source: Claude AI
ORGHPS Germination Guide: Sow @ 4C for 3 weeks, then place @ 20C.