Field Thistle
Cirsium discolor
- Native to:
- Canada, United States, Virgin Islands
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:
- jul,aug,sep,oct
- Bloom Colors:
- pink, purple
Wildlife Benefits
- Bees:
- ★★★★☆ Documented bee visitation (GBIF)
- Butterflies & Moths:
- ★★☆☆☆ Documented Lepidoptera association (GBIF)
- Caterpillars:
- ★☆☆☆☆ Recorded caterpillar host plant (HOSTS Database)
- Hummingbirds:
- ★☆☆☆☆ Documented hummingbird visits (GBIF)
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:
- birds, butterflies, bees
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 benefit from cold stratification for 30-60 days to break dormancy; sow in fall or after cold treatment.
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.
Where to Buy
Nationwide Seller
- Prairie Moon Nursery (nursery and seeds)
- Native Plants Nursery (nursery)