Echinochloa phyllopogon Seeds | Barnyard Grass
LATIN NAME: Echinochloa phyllopogon
COMMON NAME: Barnyard Grass
Plant Profile
Late watergrass is a robust annual of the grass family, native to the rice fields of East Asia and now a weed of rice wherever that crop is grown. It reaches fifty to a hundred and twenty centimetres, with a purple-tinged base, broad flat leaves and a dense, nodding panicle whose branches carry rows of small, awned spikelets.
It is a close mimic of rice. The two germinate together, the seedlings look alike until the third leaf, and the plant grows to the same height as the crop, so it is hard to see from the bank and hard to pull by hand once the field is flooded. It sets seed before the rice is harvested, and that seed shatters into the mud.
Science & Biotechnology
The species is one of the most studied herbicide-resistant weeds in the world. Populations in Californian rice have evolved resistance to propanil, to the ACCase inhibitors used against grasses, and to the ALS inhibitors, and some carry resistance to several of these at once through enhanced metabolism rather than through a single target mutation.
The mechanism has been traced to cytochrome P450 genes of the CYP81A family, which oxidise the herbicide before it can act. Because the same enzymes handle several unrelated chemistries, a population that survives one herbicide can survive others it has never met, which is why the advice in rice is to rotate modes of action and to use water management and crop rotation alongside chemistry.
Uses & Benefits
In its native range the plant is cut for fodder, and the grain is eaten in times of scarcity, but it is nowhere a crop of importance. Its real significance is negative: it is one of the weeds that costs rice growers most, both in lost yield and in the cost of control.
In a garden it has a place only as a curiosity of wet ground, in a bog garden or at the edge of a pond, where its arching heads and purple stem base are genuinely handsome. It should not be grown near a rice field, and where it is a listed weed the seed should not be moved at all. The plant is also a host for rice pests and for the nematodes that carry rice viruses.
Growing from Seed
Sow in late spring on the surface of wet mud at 25-35 °C, and keep the pot standing in two centimetres of water. The seed needs light and will not germinate under a deep covering, which is why it comes up so readily on the surface of a paddy.
Seedlings appear within a week. They are vigorous and need no help; the difficulty is restraint, since a single plant can produce several thousand seeds and a pot left to ripen will seed the whole garden. Cut the heads before they shatter if the plant is grown for ornament. In a warm climate it will self-sow in any damp corner.
Our Take
A handsome wetland grass and one of the worst weeds of rice. Grow it in a pot, in a bog, and never let it set seed near a paddy.
Related Reading
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