Salvia carduacea aka Thistle Sage

Salvia carduacea, or thistle sage, belongs to the mint family, Lamiaceae. Its native range runs from California into northern Baja California, Mexico. Kew lists it as an annual from a subtropical region. Plants For A Future also allows for a perennial habit. In Britain, gardeners tend to grow it as a spring-sown annual. It is not native to Britain or Ireland.

The plant reaches about 2.3 feet [0.7 metres] in height. In the wild, it grows in open grassland and sandy or gravelly places. These sites lie below about 4,430 feet [1,350 metres]. The supplied sources give no species-level details about its leaves or stems. They also give no flower colour or fruit description. Plants For A Future records flowering in July. Each flower has both male and female organs, and bees pollinate it.

Thistle sage needs full sun and soil that drains well. A light, sandy soil suits it, though it also accepts loam. Plants For A Future notes a preference for rich soil. It can grow in mildly acid, neutral, or mildly alkaline ground. Soil may be dry or moist, but excess winter wet can kill plants. Cultivated beds offer one setting where gardeners can meet these needs. Good drainage matters more than keeping the ground wet.

Cold limits its use outdoors in Britain. Plants For A Future reports brief tolerance of temperatures near 27°F [−3°C]. It may survive outdoors in milder parts of the country. An alpine greenhouse offers another way to grow it. Wild plants germinate in autumn, but British growers can sow in spring. Sow seed under glass in March or April. Germination usually takes about two weeks. Move seedlings into their own pots once large enough to handle. Plant them outside in early summer.

The seeds are edible raw or cooked. They can be roasted, ground, and mixed with other seeds for porridge. Another recorded use adds them to wheat for flavour. The seeds also serve as an ingredient in a drink. Plants For A Future lists no known medicinal uses or other uses. It records no known hazards, though that does not establish safety for every person or pet. Its weed assessment gives no warning of weed potential.