Windbreaks are very important to many acreage owners throughout Nebraska. A windbreak is used to block the wind, as the name implies. Winter winds can be very strong and a windbreak will help to reduce those winds, which will in turn reduce heating bills. Windbreaks can be built from a variety of trees and shrubs which are typically fairly tolerant of many problems. However, we do still see problems from bagworms, some fungal diseases, and weeds growing around the trees. A windbreak weed that is quite prevalent this year is wild cucumber or burcucumber.
About Wild Cucumber
Wild cucumber is an annual weed that grows up and over our windbreak trees. Due to all the rain we saw this spring, it is growing voraciously over our trees across the Nebraska countryside. It vines and has leaves similar to cucumber plants. The leaves are arranged alternately along the stem and have five triangular-shaped lobes on the leaves. The leaves are large, 4-10 cm long and 4-13 cm wide. If left on the trees long enough, a fruit will develop. The fruits of wild cucumber resemble a shorter, stouter cucumber with spines all around the outside. The plant climbs up onto our desired trees through the use of tendrils that twist around small branches to hold the plant up as it grows.
There is also a burcucumber plant which is closely related to wild cucumber. Burcucumber is also an annual weed that vines up and over windbreak trees. The leaves of burcucumber are more rounded and the lobes are not as deep as the lobes on the leaves of wild cucumber. Also, the fruits of burcucumber are much smaller and held in a groups. Wild cucumber and burcucumber are similar enough that management for both plants is the same and the names are often used interchangeably.
Managing Wild Cucumber
Wild cucumber is a plant with a shallow root system, so it pulls very easily. At this time of the year, this is really the only way to manage wild cucumber. Don’t spray 2,4-D or any other herbicide on the vines because anything that would control the wild cucumber can damage or even kill the trees that wild cucumber is vining up on. It would be best to pull it off and kill the plant before any fruits are produced to reduce the seedbed. However, at this time of the year they have already begun to produce fruits.
Since wild cucumber is an annual plant, it can be controlled with a pre-emergence herbicide in the spring. Products containing simazine will work to control this weed before it emerges next spring. Early May would be a great time to apply the chemical around the trees in your windbreak to make sure it is in the soil before the wild cucumber germinates. If you are having troubles with this weed this year due to the excess moisture, it would be beneficial to use the simazine next spring or you could have a similar or worse problem next year.