A non-native grass of the United States, crabgrass (Digitaria sanguinalis) belongs in the Poaceae family. Approximately 300 species occur in semitropical and tropical locations of Asia, Africa, North America and Europe. The grass produces flat, spreading blades close to the ground. Considered a weed, crabgrass is quite invasive once established. It has the ability to outcompete other grass species.
The origin of the crabgrass seed can be traced back to Africa where the Europeans first collected the harvested seeds and brought them back to Europe, according to the Samuel Roberts Noble Foundation. Once in Europe, crabgrass was grown as an animal forage and as a food additive. The seeds were also fermented to manufacture beer. In Africa, the seeds of crabgrass are known as, Fonio, and still remain a prominent staple in many locations.
Importation into the United States
In the 1800s crabgrass seeds were brought across to the United States from Europe by immigrants. The early settlers grew the grass and harvested the seeds, which they would use like millet. They would bake crabgrass seeds in breads and porridge. In 1849 the United States Department of Agriculture imported crabgrass seeds to plant for a forage for draft horses. When the turn of the century arrived crabgrass seeds were rarely used in culinary dishes, according to the North Vernon Plain Dealer and Sun. Fields of crabgrass were commonly planted for animal forage all the way into the 1940s.
Crabgrass became an extremely invasive weed in parts of North America where it escaped cultivation. It quickly took up residence in cotton fields and corn fields, where it was virtually impossible to eradicate before the advent of selective herbicides. The grass easily takes up residence in disturbed locations or cultivated fields. It grows in low clumps.
The harsh climate of Africa has caused crabgrass to evolve so it can withstand harsh conditions where periods of drought or excessive rain exist. Certain species of crabgrass have even adapted to withstanding extreme winters in parts of the United States. A prolific seed producer, one clump of crabgrass can produce 150,000 seeds per year. The seeds can be dormant in the soil for years until the conditions are ideal for the grass to begin to grow, according to Michigan State University.
For 50 years crabgrass has plagued gardeners and commercial farmers, according to Texas A & M University. Maintaining a thick turf can help eliminate crabgrass from lawns. Due to its origin of growing in Africa close to the equator, crabgrass seeds have evolved to require ample sunlight in order for germination to occur. If the seeds do not receive abundant sunlight, germination will never take place and the seeds will be dormant. Maintaining a thick turf helps cut off the light to the crabgrass seeds so germination never occurs. Numerous herbicides also exist for crabgrass control.