Astragalus complanatus Seeds | Sha Yuan Zi
LATIN NAME: Astragalus complanatus
COMMON NAME: Sha Yuan Zi, Flatstem Milkvetch
Plant Profile
Sha Yuan Zi is a low, twining perennial legume, 30-60 cm tall, with pinnate leaves and small yellow flowers in summer. The seed is the part used, flat and kidney-shaped, and it is one of the standard herbs of Chinese materia medica.
The plant grows in dry grassland and on sandy slopes in northern China, and it has a deep taproot that lets it survive drought. In cultivation it is grown as a field crop rather than a garden plant, and it is harvested in autumn when the pods ripen.
Astragalus complanatus is one of a large genus that includes the medicinal astragalus of commerce, Astragalus membranaceus. The two are related but not interchangeable, and the Chinese names distinguish them clearly even when English translations do not.
Science & Biotechnology
The seed contains flavonoids, saponins and polysaccharides, and extracts have been studied for antioxidant activity and for effects on the immune system in laboratory and animal work. The clinical evidence in humans is limited, and most of the literature is Chinese-language and of variable quality.
Astragalus as a genus is a vast one, with over two thousand species, many of them toxic to livestock because they accumulate selenium or produce swainsonine. That is why identification matters: the medicinal species are specific, and a misidentified plant is not a substitute.
The seed is used in Chinese practice for what is described as deficiency of liver and kidney yin, and it appears in formulas rather than as a single herb. It is not a culinary seed and should not be eaten casually.
Uses & Benefits
The seed is used in Chinese herbal formulas, usually roasted or processed, for a range of conditions described in traditional terms. It also appears in some patent medicines and in herbal teas sold in Chinese communities.
In agriculture the plant is a minor forage legume in northern China, and it is used to stabilise sandy soil. Commercially the seed is a traded herb, and the garden seed trade supplies growers who want to produce their own material. It is not a plant for self-treatment without professional advice. Traditionally the seed is dry-fried until it smells nutty before being decocted, a step said to reduce its tendency to upset the stomach.
Growing from Seed
Scarify the seed lightly and soak it for twelve hours before sowing at 1.5 cm deep, 20-22°C. Germination takes one to three weeks. The seed coat is hard, and untreated seed can sit for a month without sprouting.
Plant out at 30 cm apart in full sun and well-drained, preferably sandy soil. The plant is drought tolerant once established and dislikes wet ground. Water through the first summer only. Support the twining stems with a low net if the site is windy, and harvest the pods when they turn papery but before they shatter. Pods ripen unevenly up the stem, so pick the earliest by hand and leave the rest for a second pass a fortnight later.
Our Take
An agricultural and medicinal plant rather than a garden one, worth growing only if you have a use for the seed and a dry sunny row.
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