Unknown vine - Ask Extension
This vine grows rapidly in my mostly shaded yard that’s covered in Japanese pachysandra. I’ve never seen it flower in the few years I’ve lived h...
Knowledgebase
Unknown vine #942489
Asked August 15, 2026, 12:41 PM EDT
This vine grows rapidly in my mostly shaded yard that’s covered in Japanese pachysandra. I’ve never seen it flower in the few years I’ve lived here.
Montgomery County Maryland
Expert Response
While flowers are a key feature to help confirm plant ID, sometimes the foliage is distinctive enough. This looks like Sweet Autumn Clematis (Clematis paniculata / terniflora), an invasive vine that doesn't flower until late summer or autumn (if it's old enough and has enough sun to bloom). This species is commonplace and found across the state, and the seeds are windblown, so could have drifted in from a plant growing quite a distance away.
As a perennial plant, its removal will entail a thorough digging-out of its root system, or treating it with a systemic herbicide to kill the roots. There is no herbicide that will only kill the Clematis without also harming the Pachysandra if the spray contacts the groundcover's leaves, but Japanese Pachysandra is invasive too and also found in natural areas across the state, so ideally it should be removed and replaced at the same time, if feasible.
If you want to keep the Pachysandra for now, you'll either have to dig out the Clematis (which will likely kill a bit of Pachysandra in the process, until it fills back in) or cut back the vine, wait for regrowth, and then treat that smaller amount of foliage with a systemic herbicide spray. Or, you might be able to find a systemic herbicide that has instructions for treating the stump instead, which needs to be done very soon (a matter of minutes) after making the cut at the base of the vine's main stem(s). If the vine isn't old enough yet to have a more woody, thick main stem, that approach might not work as well as the foliar spray. Shield any Pachysandra from overspray as best you can (a disposable scrap piece of cardboard box or large piece of plastic can be useful), but expect that some collateral damage might occur. In that case, the degree of Pachysandra damage might be similar between using herbicide and digging out the vine.
The other alternative to herbicide and digging is to keep cutting down all vine growth repeatedly until it stops coming back. That process may take a while (months, potentially), but eventually will starve the vine's roots so it has no more energy reserves to keep regrowing. Each time it's forced to produce new leaves after being cut back, it's using-up stored root energy. If that new growth is removed promptly so it doesn't have time to photosynthesize, that will prevent the roots from "recharging" that energy supply. You might need to check on cut-back Clematis weekly (or twice weekly) to catch any regrowth that needs removal, at least until the plant goes dormant (if it hasn't fully died out by autumn), and which point the process continues in spring.
Miri
As a perennial plant, its removal will entail a thorough digging-out of its root system, or treating it with a systemic herbicide to kill the roots. There is no herbicide that will only kill the Clematis without also harming the Pachysandra if the spray contacts the groundcover's leaves, but Japanese Pachysandra is invasive too and also found in natural areas across the state, so ideally it should be removed and replaced at the same time, if feasible.
If you want to keep the Pachysandra for now, you'll either have to dig out the Clematis (which will likely kill a bit of Pachysandra in the process, until it fills back in) or cut back the vine, wait for regrowth, and then treat that smaller amount of foliage with a systemic herbicide spray. Or, you might be able to find a systemic herbicide that has instructions for treating the stump instead, which needs to be done very soon (a matter of minutes) after making the cut at the base of the vine's main stem(s). If the vine isn't old enough yet to have a more woody, thick main stem, that approach might not work as well as the foliar spray. Shield any Pachysandra from overspray as best you can (a disposable scrap piece of cardboard box or large piece of plastic can be useful), but expect that some collateral damage might occur. In that case, the degree of Pachysandra damage might be similar between using herbicide and digging out the vine.
The other alternative to herbicide and digging is to keep cutting down all vine growth repeatedly until it stops coming back. That process may take a while (months, potentially), but eventually will starve the vine's roots so it has no more energy reserves to keep regrowing. Each time it's forced to produce new leaves after being cut back, it's using-up stored root energy. If that new growth is removed promptly so it doesn't have time to photosynthesize, that will prevent the roots from "recharging" that energy supply. You might need to check on cut-back Clematis weekly (or twice weekly) to catch any regrowth that needs removal, at least until the plant goes dormant (if it hasn't fully died out by autumn), and which point the process continues in spring.
Miri
Thank you so much! You’ve been more helpful than I even anticipated. Thanks for this free service.
You're welcome!
