Mark Renz, UW-Extension weed scientist
Department of Agronomy
UW-Madison College of Agricultural and Life Sciences
Total time: 3:15
0:20 – What are they?
0:50 – What to do about them
1:40 – Impact on other species
2:14 – Identifying them
3:02 – Lead out
Lorre Kolb: Vines taking over. We’re visiting today with Mark Renz, Extension Weed Specialist, Department of Agronomy, University of Wisconsin-Madison/Extension, in the College of Agricultural and Life Sciences, and I’m Lorre Kolb. Mark, we have these vines growing all over these buildings; are they plants? Are they weeds?
Mark Renz: Yeah, so in August, right around this time, we always get these vines that have these small white flowers that become very, very visible and often the calls and emails I get is, “I have this new, invasive plant. Help me! What can I do with it?” Well, it turns out that these vines, one of two species that are most common in Wisconsin, are actually native to Wisconsin. Definitely considered weeds, but because they’re native are not considered invasive plants. Been here for many years, very common components of the flora.
Lorre Kolb: Is there a way to eradicate them? Should they worry about them?
Mark Renz: Yeah, and so I think it really comes down to what are the goals of your land? A lot of these times these are seen in minimally managed areas like on the side of a fence, side of a building, or in a right of way area. The one option is to do nothing. They’re annual vines. Bur cucumber and wild cucumber are the two species that we see, but they’re native species, so you could just let them persist; they’re annuals. They will die back and come back from seeds every year. That’s clearly one option, but if they’re going to pose some problem: you want to walk through that area. Vines are never pleasant to do that or if it’s an agricultural situation clearly want to manage those. They’re relatively easy to manage, but since they’re annuals, really the time to manage them is in the spring after they germinate, not now where they have a lot of biomass and are intertwined with a lot of desirable species.
Lorre Kolb: Will they take over the desirable species area?
Mark Renz: Yeah, and so the question really is that you know, what’s going to be their impact of leaving them there? If they’re present, they’re annuals, they germinate in April, will develop throughout the summer. They will potentially impact some of the health of some of the species that they grow on top of. For annual crops, they can have a significant impact. I would say for trees and some of the perennial species they really have minimal long term impact. It’s more of a cosmetic issue or an issue of harvesting or walking through that environment.
Lorre Kolb: So, how do you differentiate these two different plants? We have the bur cucumber and the wild cucumber.
Mark Renz: Right, and so they’re actually, from a distance, or when you’re driving by at 60 miles per hour they can be really tough to differentiate. Both have white flowers, relatively large green leaves. The bur cucumber leaves are actually quite less pointed, as compared to the wild cucumber. So, the wild cucumber will look more like a hand, where the bur cucumber will be much more rounded. The other easy way to differentiate between the two is to look at the fruits. Bur cucumber will have a very distinct fruit that is around the size of a golf ball, even maybe upwards of a tennis ball that has distinct spines on it, whereas bur cucumber has these really small fruits that are about pea sized and they’re clustered in groups of two to five, but they’re both native. They germinate in early April and they’ll have very similar cotyledons. They’ll look very similar to normal cucumbers that we plant in our garden.
Lorre Kolb: We’ve been visiting today with Mark Renz, Extension Weed Specialist, Department of Agronomy, University of Wisconsin-Madison/Extension, in the College of Agricultural and Life Sciences, and I’m Lorre Kolb.