9
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
