Cirsium occidentale, also known as cobwebby thistle, is a biennial/perennial native plant found along the coast of California. It forms a rosette of gray, woolly leaves in its first year before sending up upright flowering stalks in its second year that can reach 2-3 feet tall. The showy pink, purple, or white flowers bloom from spring to summer and attract many pollinators. Cobwebby thistle is drought tolerant, easy to grow, and provides good habitat for birds and insects.

1. Cobwebby Thistle – Cirsium occidentale vars. californicum & occidentale
(SEER-see-um ox-ih-den-TAY-lee cal-ih-FOR-ni-kum)
Family: Asteraceae (Sunflower Family)
Native to: Much of coastal California (var. californicum also in Sierras); on coast, in grasslands, coastal
dunes, oak woodland, coastal scrublands. Var. californicum also in pine-oak woodlands, riparian
woodlands, chaparral. Both vars. also in disturbed places.
Growth characteristics: biennial/perennial mature height: 2-3 ft. mature width: 2-3 ft.
Robust, upright, evergreen thistle with gray-green spiny leaves. Forms a rosette of gray woolly and spiny
leaves the first year and blooms the second year. May survive 3-4 seasons in S. CA.
Blooms/fruits: Blooms in spring/summer, usually sometime between Mar-July. Flowers are clustered in
showy ‘thistle heads’. Var. californicum has lighter flowers (white, lavender or pink) while var.
occidentale (most commonly available) has bright magenta or purple flowers. Flowering heads have hairs
which give them a cobwebby appearance (hence the common name).
Uses in the garden: Most often used as accent plant and for its habitat value. Very showy and unusual as
an accent plant – interesting foliage. Stems/stalks can be peeled & eaten raw.
Sensible substitute for: Non-native thistles; other purple-flowered annuals.
Attracts: Excellent all-round habitat plant. Many insects (bees, butterflies, others) utilize the nectar and
pollen. Larval (caterpillar) food for Lady butterflies. Hummingbirds nectar at the flowers; other birds
use plants for cover, dried flowers for nesting materials and seeds for food.
Requirements:
Element Requirement
Sun Full sun to light shade
Soil Any well-drained soil; var. occidentale is native to sandy soils
Water Drought tolerant. Can take no summer water (dies back) to occasional water.
Fertilizer None; thrives in nutrient-poor soils
Other
Management: Easy to grow. Will self-seed on bare ground in some gardens. Not invasive.
Propagation: from seed: soak seeds overnight before planting. Plant winter/early spring. Seeds
collected from higher elevations and northern sources may benefit from 2-week cold treatment.
Plant/seed sources (see list for source numbers): 1, 2, 13, 19, 21 1/25/17
© Project SOUND

2. Cirsium occidentale - Cobwebby thistle