Wavyleaf Thistle
Wavyleaf Thistle
Cirsium undulatum (Nutt.) Spreng.
Asteraceae (Sunflower Family)
▲ ▼ seedlings in rosette stage
▲ plant initiating flowering
▲ ▼ mature, flowering plants
▲ ▼ mature, flowering plants (above plant showing white leaf undersides and green leaf upper sides)
▲ ▼ mature, flowering plants
▲ ▼ flowers/inflorescences
▲ ▼ mature inflorescences after flowering
▲ mature plant with flower bud and involucre open to disperse seed
▲ ▼ mature, flowering stem, showing that leaf bases do not extend down the stem
Cirsium undulatum (Nutt.) Spreng., Wavyleaf Thistle: (Bayer Code: CIRUN; US Code: CIUM)
- Native, creeping-perennial thistle that produces branched creeping roots to produce colonies of mostly solitary-stemmed plants that grow 1-3 feet tall
- Both stems and leaves appear gray-green, grayish or whitish due to many soft, white hairs on stems and one or both sides of the leaves
- Leaves are lobed, but not as deeply lobed as yellowspine thistle (Cirsium ochrocentrum), leaf bases do not extend down the stems (as they do on yellowspine thistle)
- Leaves are gray-green to whitish, with spine-tipped lobes and wavy leaf margins, plus leaves may twist and curl along their 5-8 inch length
- Flowers are usually pale pink, but can be white to a dusty deep pink in color
- Base of head is urn-shaped, and bracts on base of head have whitish midvein and are tipped with a short, outspread, tan to brown spine
- Found in dry prairie soils from Canada to Texas
This is one of the native thistles that is sometimes mistaken for an invasive thistle species.
Native thistles provide food and nectar for native insects (including bees and butterflies), birds and other animals, and generally should not be killed indiscriminately.
Maintaining proper grazing levels can often reduce their unwanted increase in pastures and rangeland.