Coreopsis tinctoria Seeds | Plains Coreopsis

Plains Coreopsis (Coreopsis tinctoria) with bright yellow daisy flowers and maroon centres in a meadow — Plains Coreopsis (*Coreopsis tinctoria*): Asteraceae, the prairie annual that dyes cloth orange and, grown at altitude in Xinjiang, is sold as snow chrysanthemum tea.

LATIN NAME: Coreopsis tinctoria

COMMON NAME: Plains Coreopsis, Calliopsis, Golden Tickseed

Plant Profile

Plains coreopsis is a slender, upright annual, thirty to eighty centimetres tall, with fine, branching stems and thread-like leaves that give the plant an open, airy look. The flower heads are the size of a small coin, with bright yellow ray florets around a dark maroon centre, and they are produced in loose, flat-topped clusters from midsummer until the first frost. Each head lasts a few days, but new ones keep coming, and a patch in full flower has a warm, almost luminous quality.

The species is native to the Great Plains and the prairies of North America, where it grows in ditches, roadsides, wet meadows and disturbed ground, and it has naturalised widely beyond that range. It is an annual that depends entirely on seed, germinating in spring, flowering within ten weeks and setting quantities of small, dark, flat seed that scatter as the heads dry. In the garden it self-sows reliably, moving around the border from year to year, and it is one of the easiest plants to establish in a meadow or a wildflower strip. The common name tickseed refers to the shape of the seed, which is said to resemble a tick.

Science & Biotechnology

The flowers contain chalcone pigments, principally okanin and its glycosides, together with flavanones such as marein and flavanomarein, and these compounds are responsible for both the deep orange dye and much of the pharmacological interest. Extracts have been studied for antioxidant activity, for inhibition of alpha-glucosidase, and for effects on blood glucose and blood lipids in animal models. A related line of work has examined the plant’s selenium content when grown on selenium-rich soils, and its capacity to accumulate the element.

The dye chemistry is older than the pharmacology. The flowers yield a warm yellow-orange on wool and silk with an alum mordant, and the plant was used by several Native American peoples for that purpose and for body paint. In China, Coreopsis tinctoria is grown at high altitude in Xinjiang and sold as snow chrysanthemum, a tea marketed for blood pressure and blood sugar, and this trade has generated a body of analytical work comparing the flavonoid profile of flowers from different origins. The species is also used in restoration seed mixes, where its fast establishment and long flowering season make it valuable for pollinators, though it can dominate a newly sown meadow for a season or two before the perennials take over.

Uses & Benefits

The main garden use is the meadow, the wildflower strip and the cutting garden, where the plant’s long season and easy self-sowing do most of the work. It is also useful in a pot on a sunny terrace, where it will flower continuously if deadheaded, and as a filler in annual plantings, where its fine texture contrasts well with broad-leaved subjects. The flowers are good for cutting, lasting several days in water, and they hold their colour when dried.

The tea trade is the other use. Snow chrysanthemum is sold as dried flower heads and brewed as a reddish-amber infusion with a mild, slightly sweet, hay-like taste, and it is taken for blood pressure and blood sugar in the same way as other herbal teas. It is not a medicine, and anyone on medication for either condition should treat it as a possible additive rather than a replacement. The plant is not used in the classical Chinese materia medica; its reputation in China is recent and commercial.

Growing from Seed

Sow directly where the plants are to flower, because the taproot resents transplanting. Scatter the seed on prepared ground in spring, after the last frost, and rake it in lightly; light is needed for germination, so do not bury it. Keep the ground moist until the seedlings are up, which takes seven to fourteen days. Thin to twenty centimetres apart, or leave the patch to sort itself out, which it will.

The plant tolerates poor, dry soil and flowers more prolifically on it; rich ground produces soft growth and fewer flowers. Full sun is essential. Deadhead to prolong flowering, or leave the last heads to ripen for self-sowing. In cold climates the species behaves as a hardy annual and returns from seed each year, while in mild climates it may germinate in autumn and overwinter as a small rosette. It needs no staking in ordinary conditions, and it is not troubled by pests.

Our Take

One of the most useful annuals for a meadow or a cutting patch, and the cheapest colour in the garden. Sow it once, let it seed, and it will come back without being asked.

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