Wild Cucumber Invasion
Have you noticed trees and shrubs along the roadside covered by a long vine with a yellow/greenish-white flower?
As a friend described it to me recently, it looks like some extraterrestrial invasion! It is wild cucumber, Echinocystis lobata, and there is a bumper crop this year. It is an annual, native to most of North America, and preferes low lying areas, woodlands, and areas with some shade. The vines grow 25 to 30 feet long with tendrils that coil around anything they touch.
About Wild Cucumber
Wild cucumber sprouts from seed in early spring. It is a fast-growing annual and is often overlooked until it begins to engulf trees and shrubs. Once it blooms, as it has these past few weeks, it becomes even more obvious. The star-shaped leaves resemble a maple leaf and have 5 to 7 pointed lobes, alternately placed on the stem. The seed pods are oval and grow up to 2 inches long. They are covered with sharp spines that, when ripe, burst open to disperse four flat spindle-shaped brown or black seeds.
Although usually considered a weed, wild cucumber can be cultivated. Seeds can be sown as soon as the soil warms in the spring. Because it grows so quickly, it is great for covering a pergola, arbor, or along a fence or low structure. In addition, the flowers are prolific and quite fragrant. Few nurseries carry the seed, but one that does is Prairie Moon Nursery in Minnesota at www.prairiemoon.com. This year it will be quite easy to collect your own seed from the many plants that are growing in the area. The pods burst open and expel the seeds as soon as they are dry, so they must be bagged prior to drying in order to collect the seeds.
If wild cucumber is a weed in your landscape, it is easy to control. Although not considered invasive, because it is native to Wisconsin, it certainly is aggressive and will take over trees, bushes, and small creatures in a single bound. Well, maybe not small creatures. It just seems that way sometimes.
- If possible, pull or hoe the plants early in the spring as soon as they are found. The seedlings look exactly like garden cucumbers. If they are more established, repeated mowing before they set seeds will keep them in check. If they have progressed to the point that they are growing up into trees and bushes, simply pull them out and discard them. Ideally, get them out BEFORE they go to seed. This will reduce the number of plants in the area over time.
- Chemical controls may be used when necessary. Dicamba, the active ingredient in some post-emergent herbicides, is one option. However, do not use it under the canopy of trees and shrubs as it can be taken up through plant roots. Rain or irrigation water can wash it into the root zone where it will be a problem.
- Another option is glyphosate, the active ingredient in post-emergent herbicides such as Round-Up. It can be applied to young plants early in the season. This product may be used around trees as it will not be absorbed by the roots or bark. However, it also kills almost anything green and growing that it touches, so take care to keep it off desired plants. Always read and follow directions when using any chemical control.
Certified Master Gardener