Cirsium horridulum

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Purple Thistle, Yellow Thistle

Asteraceae (Compositae)

Plant Specifics

Form:Flower
Size:1-4 ft tall by 1-2 ft wide
Life Span:Biennial
Flower Color:Regionally variable: white, pink, purple, yellow
Fruit Color:White
Phenology:Overwinters as a basal rosette. Blooms in spring.
Noted for:Showy flowers, Interesting foliage, Thorns

Landscaping

Recommended Uses:Natural landscapes including meadows and butterfly gardens.
Considerations:Purple thistle is a thorny plant - be very careful when handling.
Propagation:Readily self seeds. Following pollination the flower head can be bagged to collect the seed head which follows.
Availability:Seed
Light: Full Sun,  Part Shade
Moisture Tolerance:
always floodedextremely dry
 (Somewhat moist, no flooding ----- to ----- Somewhat long very dry periods)
Moisture Tolerance: Somewhat moist, no flooding ----- to ----- Somewhat long very dry periods
Salt Water Flooding Tolerance:Not salt tolerant of inundation by salty or brackish water.
Salt Spray/ Salty Soil Tolerance:Some tolerance to salty wind but not direct salt spray.
Soil or other substrate:Sand
Soil pH:6.1 - 7.8

Ecology

Wildlife:
 

The seeds are rich in oil, an important food source for seed-eating birds. 

Insects:
   

  • Larval host to little metalmark (Calephelis virginiensis) and painted lady (Vanessa cardui) butterflies.
  • Nectar source for native butterflies and bumblebees.  Bees documented in Florida include  Evylaeus pectoralis, Halictus ligatus, Lithurgzcs gibbosus, Megachile brevis pseudobrevis, and the non-native Apis mellifera (honeybee) (Deyrup et al. 2002).
  • Beetles eat the flowers. 
  • Provides nesting material for some native bees (based on information provided by the Xerces Society to the Lady Bird Johnson Wildflower Center)

Native Habitats:Coastal plain, edges of salt marshes, pinewoods, prairies and disturbed areas.

Distribution and Planting Zones

Natural Range in Florida
USDA Zones

Suitable to grow in:
10A 10B 11 8A 8B 9A 9B 

USDA zones are based on minimum winter temperatures

Comments

Ethnobotany:Members of the Seminole tribe used parts of this plant to make blowgun darts.