Clarkia unguiculata aka Clarkia

Clarkia unguiculata is an annual in the evening primrose family, Onagraceae. Gardeners also call it elegant clarkia or butterfly flower. Other names include flower of love and swan flower. Its native range runs from California into northern Baja California, Mexico. It grows in a temperate climate. Wild plants grow on dry slopes in chaparral. Clarkia elegans is a synonym used for this species.

Plants grow upright and branch from thin stems. Garden height ranges from about 1.6–3.3 feet [0.5–1 metre]. Spread ranges from about 0.3–1.6 feet [0.1–0.5 metres]. The stems carry scattered, narrow, lance-shaped leaves. Plants reach their full size within one growing year. Flowers open in late spring and early summer. They grow from the leaf axils near the stem tops. Each flower has four paddle-shaped petals, with gaps between them. Colours include pink, purple and red, with white less frequent. The stamens stand out, with bright red anthers at their tips.

Grow this clarkia in sun or partial shade. It suits sandy or loamy soil that drains well. Choose slightly acid soil with a moderate level of nutrients. Rich soil promotes leaves at the cost of flowers. Moist soil suits it, though it tolerates some drought. It does not suit hot, humid conditions. The RHS gives it a UK hardiness rating of H6. Sow seed where plants will grow, in early spring or autumn. Avoid moving seedlings, and cover autumn sowings with cloches through winter. Cut plants back once flowering ends.

This annual suits flower beds, borders and informal cottage gardens. It also fits gravel gardens, wildflower meadows and wildlife plantings. The RHS lists coastal gardens and city courtyards among suitable settings. Gardeners can grow it for cut flowers, too. PFAF records its value for attracting wildlife. Flowers also yield green and gold dyes. Pests seldom cause trouble, according to the RHS. Downy mildew can occur, as can root, stem and foot rots.

PFAF lists the seeds as edible, either raw or cooked. They can also be milled and eaten as dry meal. Their tiny size makes gathering them a slow task. PFAF gives the plant a low food-use rating. It reports no known hazards, but this does not establish safety for pets. The same source records no known medicinal use. It also reports no weed potential for this species.