Purple Thistle Cirsium horridulum
Other Common Name(s):
- Phonetic Spelling
- SIR-see-um hor-id-YOO-lum
- Description
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Bull Thistle is a native herbaceous annual/biennial or short-lived perennial plant in the Asteraceae (daisy) family that is native to North America on the Coastal Plain from southern Maine to Florida and west to Texas. Its name comes from the Greek kersion which means thistle. The plant is spiny all over with a tall branching stem that contains large yellowish or red-purple flower heads. The plant often grows 2 to 5-1/2 feet tall (sometimes as high as 8 feet) with clasping leaves that are 8-24 inches long. It is often found along the edges of salt marshes, fields, shores, savannahs, roadsides, disturbed areas and waste places. In rare instances the blossom is pale yellow to almost white. It is also a pasture weed in the South where the blossom is often reddish purple instead of yellow.
Bull thistle prefers sunny, open areas and can tolerate some shade. It grows in all types of soils from moist to dry conditions, but it doesn't do well sitting in salt or brackish water. It grows best in sandy soil. It is propagated via seed, but expect it to take two years until it flowers.
It is a high-value nectar plant for bees and butterflies and the songbirds eat the seeds and use the tufts of the seeds for their nests. The seeds are rich in oil, an important food source for seed-eating birds. It is the host plant for the Little Metalmark butterfly (Calephelis virginiensis), which has three to five broods from March-October, and Painted Lady Butterfly (Vanessa cardui) which have one to three flights in the east from May-October and three to four flights in south Texas from October-April. Flowers are also attractive to hummingbirds. Members of this genus support the following specialized bees: Thistle Long-horned bee Melissodes desponsus, plus Osmia (Helicosmia) chalybea and Osmia (Helicosmia) texana.
Bull thistle is a great option in a meadow garden or naturalized area when looking for native host plants for the Little Metalmark butterfly or the Painted Lady butterfly. Select with care, as this species may spread into areas (such a lawns and flower beds) where thistles are not wanted. Some gardeners object to their spininess.
Quick ID Hints:
- White densely wooly underside of the leaves.
Insects, Diseases, and Other Plant Problems: No significant problems.
- See this plant in the following landscape:
- Cultivars / Varieties:
- var. horridulum
- Tags:
- Cultivars / Varieties:
- var. horridulum
- Tags:
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Attributes:
- Genus:
- Cirsium
- Species:
- horridulum
- Family:
- Asteraceae
- Life Cycle:
- Annual
- Biennial
- Perennial
- Recommended Propagation Strategy:
- Seed
- Country Or Region Of Origin:
- Coastal Plain from southern Maine to Florida; west to Texas.
- Distribution:
- AL , AR , CT , DE , FL , GA , LA , MA , MD , ME , MS , NC , NH , NJ , NV , NY , OK , PA , RI , SC , TN , TX , VA
- Wildlife Value:
- The seeds are rich in oil, an important food source for seed-eating birds and use the tufts of the seeds for their nests. It is the host plant for the Little Metalmark (Calephelis virginiensis), which has three to five broods from March-October, and Painted Lady Butterflies (Vanessa cardui) which have one to three flights in the east from May-October and three to four flights in south Texas from October-April. Flowers are also attractive to hummingbirds. Members of the genus Cirsium support the following specialized bees: Melissodes (Heliomelissodes) desponsus, Osmia (Helicosmia) chalybea and Osmia (Helicosmia) texana.
- Play Value:
- Attracts Pollinators
- Wildlife Food Source
- Wildlife Larval Host
- Particularly Resistant To (Insects/Diseases/Other Problems):
- Deer don't bother them.
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Whole Plant Traits:
- Plant Type:
- Annual
- Native Plant
- Weed
- Wildflower
- Woody Plant Leaf Characteristics:
- Deciduous
- Habit/Form:
- Erect
- Growth Rate:
- Medium
- Maintenance:
- Low
- Texture:
- Coarse
- Appendage:
- Spines
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Cultural Conditions:
- Light:
- Full sun (6 or more hours of direct sunlight a day)
- Partial Shade (Direct sunlight only part of the day, 2-6 hours)
- Soil Texture:
- Clay
- Loam (Silt)
- Sand
- Soil pH:
- Alkaline (>8.0)
- Neutral (6.0-8.0)
- Soil Drainage:
- Good Drainage
- Moist
- Occasionally Dry
- NC Region:
- Coastal
- Piedmont
- USDA Plant Hardiness Zone:
- 5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b, 9a, 9b, 10a, 10b
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Fruit:
- Fruit Color:
- Cream/Tan
- Fruit Value To Gardener:
- Showy
- Display/Harvest Time:
- Fall
- Fruit Type:
- Achene
- Fruit Length:
- < 1 inch
- Fruit Width:
- < 1 inch
- Fruit Description:
- Seeds are produced singly in a flat, brown fruit about 1/10 of an inch long. Seeds produce a feathery pappus (similar to dandelion ‘seeds’) which help disperse the seeds.
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Flowers:
- Flower Color:
- Cream/Tan
- Gold/Yellow
- Pink
- Purple/Lavender
- Red/Burgundy
- White
- Flower Inflorescence:
- Head
- Flower Value To Gardener:
- Showy
- Flower Bloom Time:
- Spring
- Summer
- Flower Shape:
- Dome
- Flower Petals:
- Bracts
- Flower Size:
- 1-3 inches
- Flower Description:
- 3 inch wide yellow and pink to purple disc flower heads atop multi-branched stems. Its spiny bracts may be purple or white. In the south, the blooms tend to be pinks to purples.
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Leaves:
- Woody Plant Leaf Characteristics:
- Deciduous
- Leaf Color:
- Green
- Leaf Feel:
- Prickly
- Leaf Type:
- Simple
- Leaf Arrangement:
- Alternate
- Rosulate
- Leaf Shape:
- Elliptical
- Lanceolate
- Leaf Margin:
- Lobed
- Hairs Present:
- Yes
- Leaf Length:
- > 6 inches
- Leaf Width:
- 1-3 inches
- Leaf Description:
- The leaf shape changes as the plant ages. Young (seed) leaves are elliptical. Older leaves form a basal rosette that can grow 8-24 inches long and are deeply incised and very spiny. The stem leaves are alternate with pronounced stiff spines along the edges, stiff hairs on the upper surface, and softer white hairs below.
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Stem:
- Stem Color:
- Green
- Stem Is Aromatic:
- No
- Stem Surface:
- Hairy (pubescent)
- Stem Description:
- Stems of the mature plant are branched and erect, giving it a winged appearance.
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Landscape:
- Landscape Location:
- Coastal
- Meadow
- Naturalized Area
- Landscape Theme:
- Butterfly Garden
- Native Garden
- Pollinator Garden
- Attracts:
- Butterflies
- Hummingbirds
- Pollinators
- Songbirds
- Specialized Bees
- Resistance To Challenges:
- Salt
- Wet Soil
- Problems:
- Spines/Thorns
- Weedy
