Cucumber Season?

Every year in late summer, there are two weeds in the cucurbit family that can cause problems in crops, bushes, fence lines, or trees.  Both bur cucumber and wild cucumber are problematic as they germinate throughout the season.  Their long green vines can go unnoticed early, but their tendrils allow them to climb rapidly over a crop, fence line, bush, or tree and can smother a plant.

The leaves are 5-8 inches in both length and width, with bur cucumber having very shallow lobes and wild cucumber having deep lobes. The bur cucumber leaves are more heart shaped while wild cucumber leaves are similar to a maple leaf or a five pointed star.   

📷 by Duane Rathmann | Deep lobed wild cucumber leaf appears like a five pointed star.

Bur Cucumber: This is a more common agronomic problem than wild cucumber and can be a tough weed in corn and soybeans as it germinates late in the season. Bur cucumber can germinate after a residual herbicide runs out and after a post application is made. Bur cucumber fruit develop in clusters of 6-10 egg shaped capsules that contain one seed each.

Wild cucumber: This plant is distinguished from bur cucumber as its fruit develop singularly along the vine with a pod-like container up to 2 inches long, covered with spines, and holds 4 seeds each. The pod looks a little like a tiny and spiny watermelon. The pods turns brown, and when ripe the bottom of the pod opens allowing the seed to drop to the ground. 

📷 by Duane Rathmann |Spiny wild cucumber fruit develops singularly along vine.

This weed can quickly paint the landscape with its white flowers and is sometimes grown as an ornamental on arbors.  Its flowers make its presence known every August on evergreens, bushes, evergreens, fence lines, and anything else that it finds to climb.  Its dense patches and large leaves can smother, stunt and even kill tall evergreens. 

📷 by Duane Rathmann | Wild cucumber vine climbing up an evergreen tree. Stems are angled, hairless, and have branching tendrils that entwine surrounding vegetation.

Control of wild and bur cucumber: Both wild and bur cucumber are annual weeds so control of the plant prior to seed production can be effective.   In corn, strong broadleaf pre herbicides such as Verdict® herbicide as well as Status® herbicide post offer good control. 

In soybeans, preemergence use of Sharpen® herbicide or metribuzin are effective, while post applications of Liberty® herbicide offer good control, with glyphosate offering only fair control. When in crop, be careful not to spread seeds with the combine by isolating patches and handling them separately.

The best way to remove wild cucumber from trees and shrubs where use of herbicides is not practical is to hand pull the vine as it comes off quite easily or to mow under the trees or shrubs.  

Verdict, Status, Sharpen, and Liberty are registered trademarks of BASF. All other trademarks are the property of their respective owners and use of any such trademark does not imply any affiliation with or endorsement by its owner