Cobwebby Thistle

(Cirsium occidentale)

Cobwebby Thistle (Cirsium occidentale)

Daniel S.

CC BY 4.0

Image By: Daniel S.

Recorded By:

Estimated Native Range

Summary

Cirsium occidentale, commonly known as Cobwebby Thistle, is a deciduous biennial or perennial herb native to California and Baja California, where it is found in a variety of habitats including chaparral, coastal sage scrub, and open woodlands. It can vary greatly in size, forming low clumps or towering up to 3 meters (9.8 ft) tall. The leaves are a distinctive dull gray-green to bright white, due to a dense coating of hairs, with the largest basal leaves reaching nearly 0.5 meters (1.6 ft) in length. The winged and spiny petioles support toothed leaves with triangular lobes. The inflorescence is a striking feature, with flower heads that are sphere-like and covered in large phyllaries with long, spreading spines, often heavily laced with cobweb-like fibers. The disc florets range in color from white to blood red to shades of purple, and the largest heads can exceed 8 centimeters (3.1 in) in diameter. Flowering does not occur simultaneously, which may increase the chances of pollination.

Cobwebby Thistle is valued for its unique appearance, particularly the cobweb-covered spines that give the plant its common name. It is used in native plant gardens and restoration projects for its adaptability and low water requirements. It thrives in full sun to part shade and prefers soils with medium drainage. While it is drought-tolerant, additional water can promote more vigorous growth. Gardeners should be cautious, as it can become weedy and its spines may be considered a nuisance.CC BY-SA 4.0

Plant Description

Plant Type: Herb
Height: 1-2 feet
Width: 0.5-1 feet
Growth Rate: Moderate
Flower Color: Purple, Red
Flowering Season: Fall, Spring, Summer
Leaf Retention: Deciduous

Growth Requirements

Sun: Full Sun, Part Shade
Water: Low, Medium
Drainage: Medium

Common Uses

Bee Garden, Bird Garden, Butterfly Garden, Deer Resistant, Drought Tolerant, Edible*Disclaimer: Easyscape's listed plant edibility is for informational use. Always verify the safety and proper identification of any plant before consumption., Hummingbird Garden, Low Maintenance, Rock Garden

Natural Habitat

Native to chaparral, coastal sage scrub, and open woodlands in California

Other Names

Common Names: Cobweb Thistle, Western Thistle

Scientific Names: , Cirsium occidentale, Carduus occidentalis, Cnicus occidentalis, Cnicus lilacinus, Carduus occidentalis var. coulteri, Carduus occidentalis var. occidentalis, Cirsium occidentale subsp. eu-occidentale, Cnicus neglectus,

GBIF Accepted Name: Cirsium occidentale (Nutt.) Jeps.