The invasion of the crabgrass

Crabgrass can creep over an entire lawn...but is that a bad thing? — Rasbak, Wikimedia Commons (CC BY-SA 3.0)

Late June has come and Vineyarders, when they’re not madly serving the tourist economy, are snoozing in hammocks, hurling Frisbees, tending barbeques, and enjoying countless other recreational activities on the surface where summer fun gets done: the ubiquitous lawn. It’s about this time of year you may find something has begun to creep in amongst your precious blades of fescue, something pale and sinister. (Cue John Williams’ infamous two note progression). You may think it’s a trick of the light. Not your lawn! You baby your lawn. (Let’s hear that two note progression again). You take another look. One, just one — you reach down to rip it out. (Two-note progression with a little more tempo). Oh, it seems connected to another. That seems connected to — (let’s have maximum tempo) — dozens, no scores, of little green octopi. You, friend, are in the midst of a crabgrass invasion.

Of the two major theories on how crabgrass, an immigrant from the old world, came to our shores, the government introduction theory is fuzziest, as it seems to lack verifiable documentation. It purports that in the mid 19th century, prior to the establishment of the United States Department of Agriculture, the United States Patent Office imported crabgrass for use as a forage plant for livestock. The other theory is that crabgrass seeds contaminated one or more shipments of grain to England in the 19th Century. After it flourished there, it somehow leapt to North and South America.

However it arrived, crabgrass is now found in every US state except Alaska. Whether or not it was a forage plant well over a century ago, it certainly is now. As dismaying as it might sound, you can buy crabgrass seed in bulk. For the homeowner, such a purchase might seem like a prelude to madness. But for the rancher, a grass that’s packed with nutrition and flourishes in poor soils is smart choice.

In other parts of the world, particularly Africa, crabgrass is a food crop. In the late 20th Century, an engineer from Senegal named Sanoussi DiaKite developed a husking machine for a variety of African crabgrass called fonio. The previous method of husking had been tedious manual labor. Once husked, the fonio seeds, which happen to be gluten free, can be made into pasta, bread, porridge, beer, or couscous. So the next time you find yourself in certain regions of Africa, you can have sweet revenge on an old enemy by simply devouring it. Look at your lawn long enough and it may be motivation enough to plan a trip.

Here on the Vineyard, where the linguini potential of crabgrass has yet to be tapped (take note entrepreneurs), battles for homogeneous turf are ever-raging. What many homeowners may not know is that the enemy has almost certainly established a beachhead the preceding year. The two crabgrasses rife on the Island, large or hairy crabgrass (digitaria sanguinalis) and smooth crabgrass (digitaria ciliaris) can sew up one-hundred and fifty-thousand seeds per plant. According to the Penn State Extension, since crabgrass grows quite low — lower than your mower blade can safely cut — if upper growth is mowed off repeatedly, a single grass could produce two or three crops in a season (up to four-hundred and fifty-thousand seeds). In the decade of chemical innocence following the Second World War, cuddly compounds like potassium cyanate, and even tear gas, were used to sterilize crabgrass seed in residential lawns. Today, there are saner chemical controls. Like many nurseries and garden centers on the Island, Vineyard Gardens in West Tisbury sells many of them.

“Our best selling lawn product would have to be Jonathan Green crabgrass preventer,”  said Laura Stone, nursery manager at Vineyard Gardens. “No one likes crabgrass. We have one for established lawns, and another you can put down when seeding a new lawn.” For those who are chemical shy, skip Cross Fit for the week and slip on those gardening gloves to remove crabgrass manually. A rainy day is best as the grass pulls easier. Pulling must be repeated for several years in order to work, however. A single grass can bring you back to square one. If you’re planting a new lawn, and the area is small enough, consider solarizing the area by covering the soil with clear plastic, nuking seeds that may be hiding in there. Wait for the window between late August to the first day of October if you want a new lawn and fear old crabby. According to Thomas Kowalsick of the Cornell Cooperative Extension, grass grown at that time, when property selected and fertilized, will mesh densely and make penetration by crabgrasses more difficult.

If you do find yourself harboring more crabgrass than traditional turf, there are likely support groups available. In lieu of attending one, you can take solace in crabgrass’s ability to help hide all your dandelions, chickweed, and clover.