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Cirsium altissimum is often confused with:
Cirsium discolor Flower detail
Plants that fill a similar niche:
Asclepias syriaca Form in bloom (Guilford County, NC)-Mid Summer
Betonica officinalis 2 lipped purple red flowers
Stokesia laevis Spring form

Roadside Thistle Cirsium altissimum

Other Common Name(s):

Description

Tall thistle is a wildflower that is native to the eastern half of the USA in the aster (Asteraceae) family. It can be found in both disturbed and undisturbed sites, This plant is a biennial or short-lived perennial that forms a rosette of leaves about 1 foot across the first year and blooms the second year. The bloom stem can be 3-10 feet tall depending on conditions and the amount of sunshine.

The basal leaves have spines along the margins with a few hairs and are more deeply pinnatifid than stem leaves. During the second year, the tough hairy stems appear with alternate leaves that have hairs on the upper surface and are densely hairy on the underside. These leaves vary in shape and can have lobed, entire or toothed margins. There is generally a spine at the point of the lobes or the teeth.  

Late summer into fall the individual flower heads appear with pink to purple disc flowers that are about 2 inches across. Many pollinators are attracted to the abundant nectar this plant produces. After blooming the seed heads are formed with long hairs that are wind-dispersed. The plant then turns brown and withers.

Tall thistle prefers full sun to light shade and is more shade tolerant than other thistles. It tolerates both dry and moist sites and prefers a fertile well-drained sandy or clay loam. Unlike non-native thistles, this plant doesn't become weedy and can make a wonderful addition to the native pollinator garden. Use tall thistle at the edge of forests, in naturalized areas, in meadows and pond margins. It reproduces by seed.

Non-native thistles generally bloom in spring and have more spines. 

Insects, Diseases, and Other Plant Problems: No significant problems.

See this plant in the following landscape:
Cultivars / Varieties:
Tags:
#showy flowers#biennial#purple flowers#pink flowers#deer resistant#native garden#pollinator plant#native wildflower#naturalized area#nectar plant fall#butterfly friendly#nectar plant late summer#host plant#pollinator garden#meadow
 
Cultivars / Varieties:
Tags:
#showy flowers#biennial#purple flowers#pink flowers#deer resistant#native garden#pollinator plant#native wildflower#naturalized area#nectar plant fall#butterfly friendly#nectar plant late summer#host plant#pollinator garden#meadow
  • Attributes:
    Genus:
    Cirsium
    Species:
    altissimum
    Family:
    Asteraceae
    Life Cycle:
    Biennial
    Country Or Region Of Origin:
    North America
    Distribution:
    Alabama, Arkansas, Delaware, District of Columbia, Florida, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Nebraska, New York, North Carolina, North Dakota, Ohio, Oklahoma, Pennsylvania, South Carolina, South Dakota, Tennessee, Texas, West Virginia, Wisconsin
    Wildlife Value:
    Many bees, butterflies and moths are attracted to the nectar. The caterpillars of two butterflies, Calephelis muticum (Swamp Metalmark) and Vanessa cardui (Painted Lady) use it as a host plant. Songbirds will eat the seeds.
    Dimensions:
    Height: 3 ft. 0 in. - 10 ft. 0 in.
    Width: 1 ft. 0 in. - 2 ft. 0 in.
  • Whole Plant Traits:
    Plant Type:
    Native Plant
    Wildflower
    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:
    Acid (<6.0)
    Alkaline (>8.0)
    Neutral (6.0-8.0)
    Soil Drainage:
    Good Drainage
    Moist
    Occasionally Dry
    NC Region:
    Coastal
    Mountains
    Piedmont
    USDA Plant Hardiness Zone:
    3a, 3b, 4a, 4b, 5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b, 9a, 9b
  • Fruit:
    Display/Harvest Time:
    Fall
    Fruit Type:
    Achene
    Fruit Description:
    The bullet-shaped achenes have tufts of cottony white hairs. They are wind-dispursed.
  • Flowers:
    Flower Color:
    Pink
    Purple/Lavender
    Flower Inflorescence:
    Head
    Flower Value To Gardener:
    Good Cut
    Showy
    Flower Bloom Time:
    Fall
    Summer
    Flower Shape:
    Tubular
    Flower Petals:
    4-5 petals/rays
    Flower Size:
    1-3 inches
    Flower Description:
    Flowers have disc florets only and are up to 2 inches across. Colors are pink to purple and rarely white. Each small tubular floret has 5 slender petals. The base of the inflorescence has overlapping scales. Bloom time is late summer to fall and last 30-45 days.
  • Leaves:
    Leaf Color:
    Green
    Leaf Type:
    Simple
    Leaf Arrangement:
    Alternate
    Rosulate
    Leaf Shape:
    Elliptical
    Lanceolate
    Oblanceolate
    Leaf Margin:
    Dentate
    Entire
    Lobed
    Hairs Present:
    Yes
    Leaf Length:
    > 6 inches
    Leaf Width:
    1-3 inches
    Leaf Description:
    Basal leaves are green, 6 inches long and deeply pinnatifid. Stem leaves are up to 9 inches long and 3 inches across. They are generally larger on the lower stem. Shape varies greatly and can be lanceolate, oblanceolate, or elliptic. Margins can be lobed, dentate of entire. Spines are present on the lobes and the underside is densely hairy giving it a white appearance.
  • Stem:
    Stem Color:
    Brown/Copper
    Green
    Red/Burgundy
    Stem Is Aromatic:
    No
    Stem Cross Section:
    Round
    Stem Surface:
    Hairy (pubescent)
    Stem Description:
    Stems are light green to reddish brown with longitudinal ridges and densely hairy. They are sparsely branched.
  • Landscape:
    Landscape Location:
    Meadow
    Naturalized Area
    Pond
    Slope/Bank
    Woodland
    Landscape Theme:
    Butterfly Garden
    Cottage Garden
    Cutting Garden
    Drought Tolerant Garden
    Native Garden
    Pollinator Garden
    Design Feature:
    Border
    Small groups
    Attracts:
    Bees
    Butterflies
    Moths
    Pollinators
    Songbirds
    Resistance To Challenges:
    Deer
    Drought
    Problems:
    Spines/Thorns