Digitaria is a large genus of annual plants, which grow worldwide in tropical, sub-tropical and temperate regions. Its name comes from the Latin word “digitus”, which means finger. This quite accurately describes the finger like leaves sprouting from the stem.
It is native to Europe, but has become easily naturalized in many places worldwide, including Northern USA, where it is considered a weed plant. However, due to its incredible rate of setting seed, in many parts of Africa it is grown as a crop.
There it is known as “Fonio”, and the seeds are used as a grain, ground to flour or used to make couscous. You can brew beer and make porridge with it. It can produce an amazing amount of forage for stock – up to 17 tons per
acre, and dried and bundled for use as hay.
It’s also been used as a crop in parts of Germany and Poland, and here it’s called Polish millet. It was brought to the US by immigrants to serve as grain for them as forage for their stock. Farmers often deliberately seed it into their fields, or till patches in their pasture to encourage its growth.
Although there are many species of this plant, this article will deal with the two most destructive and invasive of them, Digitaria sanguinalis, and Digitaria ischaemum.
Its name translates as “red finger”, and it is also known as large crabgrass, hairy crabgrass, finger grass, or summer grass in the southern hemisphere. It has a low, spreading habit, and resembles crab’s legs coming out from a central “body”.
It’s an annual, meaning it grows all year, sets seed and then dies. The problem lies in the fact
that one plant can produce up to 150,000 seeds, and these can very quickly take over your lawn areas.
The roots of this plant exude a toxic substance that kills other lawn grasses, and provides perfect conditions for the stems to spread. When the plant dies off in the fall, it leaves conspicuous brown patches in your lawn which are quickly colonized by next year’s seedlings. The stems themselves have nodes, or joints, which very easily sprout roots when in contact with the soil, and in this way plants can grow up to one foot in diameter.
Crabgrass can quickly become a problem, as it is more than able to flourish in hot and dry conditions, which enables it to out-compete stressed lawn grasses.
This species, to all intents and purposes, is the same as the other in its growth habits and subsequent annoyance to gardeners. There are minor visual differences only, and treatment of both species is the same.
I recommend to divide your lawn into sections, and just do one section per day. Or one per week, whatever you can handle. Then it doesn’t seem like such a huge job to do. It’s like anything, you just need to start, and you will find it gets done in no time.
If you have a horrible infestation, as a very last resort you can spot treat your lawn with an appropriate herbicide. Consult your landscaper or garden professional for formulations appropriate for your particular situation.