Even if you haven’t heard of bur cucumber, you have more than likely seen it. It’s been growing in ditches, crop fields, up trees, fences and shrubs. Bur cucumber is a bright green, fast-growing vine that climbs or spreads across the ground. As the name suggests, it is related to the cucumber, but this is not a plant that you want growing in your garden. Or on your property at all, for that matter. It can climb and kill trees, and can out-compete native plants. I’m going to discuss how to identify it, and how to try to get rid of it.
Bur cucumber is an annual plant, which means that it grows, flowers, seeds, and dies, in one year. They begin germinating in early May and quickly shoot up, allowing them to be taller and get more sunshine than plants that have not grown or germinated yet.
The leaves are roughly pentagon shaped, with a deep indent where the leaf connects to stem. The leaves are rough like sandpaper and alternate which side of the stem they are on.
The stems and bottom of the leaves are very hairy, which is a good way to tell it apart from wild cucumber. Wild cucumber plants have smooth stems.
Starting around late summer, the bur cucumber will flower. One of the few advantages of this plant is that its flowers are very attractive to bees and other pollinators in a time that there are not many plants flowering for pollinators.
These flowers will produce clumps of seeds that are surrounded by a spiky seed coat. These spiky seed coats can get caught on skin, clothes, and animal fur. The spikes stick in skin similar to stickers or slivers.
While it is not officially categorized as an invasive plant, bur cucumber is an obnoxious weed for many reasons. It spreads fast and climbs whatever it touches, whether it be tree, fence, shrub or house. It produces many seeds every year, which can live dormant in the soil for several years. The vine can grow up to twenty feet, well out of reach. Every year it spreads further, and if the population of bur cucumber is high enough, it can shade out trees, depriving them of sunlight and killing them.
Unfortunately, there is no one good way to get rid of bur cucumber. The herbicides that are effective against it will kill everything in their path, making them difficult to use in home landscape situations.
It also grows very quickly, making it time and labor intensive to pull all of the vines down from whatever tree or shrub they are climbing. It spreads and seeds itself very quickly, causing there to be more vines every consecutive year. If homeowners wait until the bur cucumber is producing seeds, the seeds are large and thorny, making it more difficult to pull the vines down. Bur cucumber has a shallow tap root based root system, which is helpful in regards to pulling the weed up by its roots.
Hand pulling the weeds is likely the most effective method of getting rid of them without harming the surrounding landscape. In the early spring while they still are small, they easily are visible because of their bright green leaves. If pulled while they still are small, they don’t have the opportunity to climb or to produce seeds, reducing the number of seeds that will be in the soil the next year.
A weed whipper also could be useful for this, but be sure to not wound any surrounding trees, as this can cause more issues.
A pre-emergent herbicide could prevent the seeds from germinating, but not all seeds will germinate in one year. To be fully rid of bur cucumber, it may take several years of being vigilant against bur cucumbers.
Bur cucumbers are a pain to have in a landscape, but as long as they aren’t shading out your tree or shrub, most of their harm is just aesthetic. Keep on top of them for a few years by catching them before they are 20 feet long, and the population will start declining. If you have any questions feel free to contact me at the Buffalo County Extension Office, at 308-236-1235, or email@example.com.