Setaria viridis Seeds | Green Foxtail
LATIN NAME: Setaria viridis
COMMON NAME: Green Foxtail
Plant Profile
Green foxtail is a slender annual of the grass family, native to Eurasia and now found in almost every temperate and subtropical country. It grows twenty to a hundred centimetres, with flat, bright green leaves and a dense, cylindrical panicle that bristles with long, green or purple-tipped awns.
The head is the reason for the name: it is soft to the touch in one direction and rough in the other, and it holds its shape through the summer, turning pale straw in autumn. The plant is shallow-rooted and short-lived, and it sets seed within eight weeks of germination, which is why it appears so suddenly in disturbed ground.
Science & Biotechnology
Green foxtail has become a model plant for the study of C4 photosynthesis. It has a small genome of about five hundred megabases, a life cycle of six to eight weeks, and it can be transformed and edited with the same tools used on rice, which makes it far easier to work with than maize or sorghum. The reference accession, A10, was released with an assembled genome in 2017.
It is also the wild ancestor of foxtail millet, Setaria italica, one of the oldest cultivated grains in China. The two interbreed where they grow together, and the weedy form is a reservoir of genes that breeders have used for disease resistance and for early maturity. Because it is a weed of arable land, the same traits that make it a good model make it hard to control in a field.
Uses & Benefits
The seed is eaten by small birds and is sold in wild bird mixes, and the plant is cut for fodder in parts of Asia. Its main agricultural role, though, is as a weed: it competes with maize, soybeans and vegetables in their first weeks and can cut yield if it is not controlled.
In a garden it is a useful annual for a wild corner, a gravel garden or the edge of a meadow, where its bristly heads catch the light and feed finches into autumn. It is also grown in teaching and research collections, and the seed is used in classrooms as an example of a C4 grass that can be raised on a windowsill in a single season.
Growing from Seed
Sow from late spring, once the soil is warm, on the surface of a light compost, and cover very lightly. The seed needs light to germinate and comes up in five to seven days at 20-25 °C. It will grow on almost any soil, but it is fastest on warm, disturbed ground.
Thin the seedlings to ten centimetres apart if a good stand is wanted, though the plant tolerates crowding. Water until it is established and then leave it. To stop it self-sowing, cut the heads as the seed begins to turn brown, or pull the plants before the seed shatters. Seed collected in late summer and dried keeps for several years.
Our Take
A weed, a model organism and a birdseed plant at once. Grow it in a wild corner, and cut the heads before it takes over.
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