Summer is a hot time for weed control issues.
One of the main concerns I get from homeowners is how to control all of the vines that start to grow up through our ornamental plants.
The three main weedy vines we see in our landscapes are greenbriar, Virginia creeper and poison ivy. All of these can be controlled when treated properly.
Greenbriar can be a major annoyance because it is often found growing in and among other plants. It will appear in the middle of a shrub or tree, often wrapping itself around the branches of the plant as it grows. Greenbriar is the common name for plants of the genus Smilax, which contains around 15 species. Its leaves are heart-shaped and appear waxy. Female plants bear seeds with a heard coat that can remain viable for several years.
When greenbriar seeds encounter conditions favorable for germination, they begin to grow and shortly develop an extensive tuber/rhizome system. This tuberous system makes greenbriar somewhat difficult to control.
The tuber stores carbohydrates for regrowth, so simply cutting the top off of the plant won’t control regrowth in future years. The best control for greenbriar is to dig up the tuber and destroy it.
Virginia creeper and poison ivy are often confused with one another. Virginia creeper has leaflets of five, while poison ivy has leaflets of three. Both are vigorous growers and can quickly consume landscape plants. Three are two control options for poison ivy and Virginia creeper growing amongst landscape plants.
First, unravel the vines from around the tree or shrub. Use protective wear when handling poison ivy. Lay the vine on bare ground or a piece of plastic and spray or sponge on a 5-percent solution of glyphosate. You can make this solution by mixing six ounces of 41-percent glyphosate with 1 gallon of water. Wait 48 hours and then cut the stump at ground level. When the vine regrows to a height of 6 inches, retreat with the same 5-percent solution.
A second option is to cut the vine as close to the ground as possible. Immediately paint the cut stem (leading to the roots) with concentrated 41-percent glyphosate. It is easiest to apply this with a foam paint brush. Simply soak the foam brush in the glyphosate herbicide and dab the cut stump.
Unfortunately, there are no herbicides available today that can be used on these vines without harming the plants they are growing on. If the vines are growing away from other landscape plants, use products containing 2,4-D and dicamba or glyphosate for best control. Remember to shield ornamental plants when using these products, as they can also be harmed or killed if contacted by the herbicide.