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Spiny Thistle Cirsium horridulum

Phonetic Spelling
SIR-see-um hor-id-YOO-lum
Description

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:
#hummingbird friendly#full sun tolerant#biennial#nectar plant#seedheads#specialized bees#NC native#spines#spiny leaves#wind dispersed seeds#disturbed areas#pollinator plant#native wildflower#wildflower garden#larval host plant#annual herb#food source fall#bird friendly#food source hard mast fruit#butterfly friendly#partial shade tolerant#bee friendly#little metalmark butterfly#painted lady butterfly#annual#weed#moth friendly#wildlife friendly
 
Cultivars / Varieties:
var. horridulum
Tags:
#hummingbird friendly#full sun tolerant#biennial#nectar plant#seedheads#specialized bees#NC native#spines#spiny leaves#wind dispersed seeds#disturbed areas#pollinator plant#native wildflower#wildflower garden#larval host plant#annual herb#food source fall#bird friendly#food source hard mast fruit#butterfly friendly#partial shade tolerant#bee friendly#little metalmark butterfly#painted lady butterfly#annual#weed#moth friendly#wildlife friendly
  • 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.
  • 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
  • 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
  • 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.
  • 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.
  • 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.
  • 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.
  • 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