Along with Iowa’s more traditional crops, two species of cucumber vines are having a bumper year. It’s not an edible kind of cucumber, but a pest that can choke out all sorts of plants, including young stands of trees. Iowa State University agronomy professor Bob Hartzler says the cucumber culprits are the wild and the burr varieties.
“There is more of it this year,” Hartzler says. “Both species start relatively late compared to some of our other weeds. In many years, when it turns dry in the summer, because of the late start, they can’t compete with the already-established vegetation. This year, with moisture throughout the growing season, it’s allowed them to thrive.”
It’s especially noticeable in the trees this year and its leaving some landowners in a pickle. Hartzler says the light green vines will grow up to 30 feet long and coil around anything they touch. He advises against using chemicals to control the weeds. “They grow in areas where it’s hard to use herbicides, simply because if they are growing up on a tree, there’s not a selective chemical that will kill the cucumber species without damaging the tree,” Hartzler says. “When you have a big problem, usually it’s a relatively small number of plants.”
Because they’re an annual, he says if you clip them off at the base, they aren’t going to regrow from that root. The seeds falling from the plant will likely grow again next year, so he says it’s best to pull the seedlings as soon as possible in the spring. Hartzler says they’re very aggressive and they’re native to Iowa so they’re not considered invasive, but he says they can be a nuisance.