Wet years fuel sweet clover growth in South Dakota

RAPID CITY (AP) – Two wet growing seasons have fueled runaway yellow sweet clover growth in South Dakota, posing problems for native grasses, cattle and cutting equipment.

KOTA-TV reports the plant with its tell-tale yellow blossoms is biennial, which means it has a two-year life cycle. That means it takes a couple of consecutive wet years to produce the wave of growth the state is experiencing.

Krista Ehlert is a range specialist with the South Dakota State University Extension Office. She told the television station that the plant spends the first year growing its root system. It then turns all its energy to above-ground growth in year two.

"We get that nice yellow color which is pretty to some people and to other people it's a bit worrisome," she said.

The plant grows so dense and so tall – sweet clover can reach anywhere between five and eight feet – that it can shade out other grasses, she said. It also grows so stringy and tough that cattle can't eat it and haying equipment can't cut through it.

Honey bees like to congregate on the plants, though, producing a mild-flavor honey from the plant's nectar. Logan Cleaver works for the Stoddard Honey company in Utah and brings hives up to South Dakota every year so the bees can feast on sweet clover.

"South Dakota's awesome and this year should be one of the better years," Cleaver said.

Ehlert said it's too early to predict whether the state will see another bumper crop of sweet clover in 2020 but the plan has impressive staying power.

"It can create hundreds of thousands of seeds and they'll stay in the soil, viable, for 30 to 40 years," she said. "I would definitely keep an eye on it."

Yellow sweet clover is native to Europe. Invasive sweet clover populations are common on the Midwest and Great Plains.