Wild cucumber is prevalent this year


Citizens concerned about the increased presence of wild cucumber have reportedly been calling the Minnesota Department of Agriculture and County Agricultural Inspector over the past three weeks about the plant.

The native plant that has become quite visible throughout a large portion of the state. In response, the Department of Agriculture issued a news release to educate area residents about the vine, providing the following basic information:

Wild cucumber is an annual plant that resembles cultivated cucumber plant varieties and is easily distinguished by its five-lobed star-shaped leaves that alternate along smooth branching vines.

The vines terminate in stringy tendrils that are used to climb structures. Plants produce many long erect racemes that contain both male and female flowers which are very fragrant and consist of six narrow and slightly twisted pale white petals.

There are significantly more male flowers per raceme, thus why after seeing the proliferation of flowers this plant produces, many people are confused by the relatively low number of fruits that emerge.

The fruit is typically an egg sized oval capsule with noticeable longitudinal veins and covered with soft prickles. Each fruit contains four chambers housing flat brown seeds. Although wild cucumber strongly resembles cultivated cucumber varieties, the fruit is not edible.

Wild cucumber can grow in a variety of habitats, but generally prefers moist soils and access to plenty of sun. Plants are most easily identified in the landscape during mid to late summer when the vines expand exponentially and flowering begins to occur.

It is commonly found growing on the edges of woodlands, shelterbelts, rights-of-ways and stream edges. Vines often climb upward into tree canopies and can form dense mats.

In most years, wild cucumber populations are not predominant in the landscape. However, in years where spring and early summer conditions are preferable, the plant can become an aggressive force in habitats where it is established.

The abundant and consistent precipitation across much of Minnesota during the early part of the 2018 growing season has most likely led to the abundance of wild cucumber currently being reported statewide.

The good news is that this native plant can be easily controlled if necessary.

The key to preventing vines from covering trees and other structures on properties is to focus on finding young seedlings following germination in the early spring.

The best places to look for seedlings or young vines is to re-visit the locations where vines were present the prior year. Young seedlings look very similar to garden cucumber seedlings and can be hand-pulled fairly easy.

Young vines will have the characteristic star-shaped leaves. If large populations of seedlings and young vines are present, herbicides may be useful. However, be very careful not to expose trees or other desirable vegetation to herbicides. To learn more about herbicide application, please consult your local University of Minnesota Extension office, a professional applicator or a landscape expert.

Once vines become too large and begin to crawl-up other vegetation, herbicides treatments should be avoided.

Vines can simply be traced back to their source and pulled out of the ground. Often people get overwhelmed with the size of matted vines in trees and other structures and feel that it is an impossible task to control this plant.

However, in most cases the highly branched vines lead back to a few source roots. If necessary, matted vines can also be pulled from trees, but after the roots are pulled and the vines die, they will begin to deteriorate.

Although wild cucumber can be aggressive and spread quickly in a growing season, landowners can curb large populations from developing by focusing on spring management of seedlings and hand-pulling vines at their ground source later in the summer.

This native plant is an annual that can only reproduce by seed. Therefore, focusing on prevention of seed production will reduce wild cucumber's presence in sensitive landscapes like managed urban areas, orchards and shelterbelts.