Everybody knows Kentucky bluegrass. It’s that good American plant that people across the country use in their lawns.
But wait – is Kentucky bluegrass really American?
It turns out it isn’t.
Kentucky bluegrass is scientifically known as Poa pratensis, which means “meadow grass”. That was the plant’s common name centuries ago in its native range – in Europe.
Meadow grass was brought to North America in the 1600s, probably by accident. It was a happy accident from the settlers’ point of view, since meadow grass made great forage for cattle. North America’s native grasses, the pioneers quickly discovered, couldn’t survive being eaten by cows day after day.
In addition to being good at surviving constant grazing, meadow grass – which soon was being referred to as “Old World meadow grass” – was also good at spreading. The plant rapidly escaped from pastures in the East Coast colonies, and started heading west. When explorers finally made it over the Appalachians to the region now known as Kentucky, they found the meadow grass had beaten them there. From its ability to travel swiftly and its deep green color, the plant acquired its modern name, “Kentucky bluegrass”.
Why do we use this invasive grass species in our lawns? After all, North America boasts over 1,000 of its own native grass species. The answer is that, for the same reason that North American grasses don’t put up with grazing, they also don’t survive regular mowing.
Kentucky bluegrass, and other European species, evolved alongside grazing animals that tended to stay put. These species needed to figure out strategies to recover from daily munching.
North American species, in contrast, evolved alongside buffalo – and as we all know, buffalo roam. Therefore, North American grass species evolved to survive being occasionally descended upon by a herd of large ungulates, and then having plenty of time to grow back before the animals returned for another meal. In the context of a yard, these species can tolerate being mowed once in a rare while, but they quickly die if mowed every week.
For a period of our country’s history, many people thought that being a good American meant having a yard filled edge to edge with an invasive grass species. Now, many people think that being a good American means celebrating our own native plants – and one way we can do that is to invite them into our yards.