If you’ve been noticing masses of showy white flowers rambling over vegetation along the roadsides, it might be Sweet Autumn Clematis (Clematis terniflora). Also known as Sweet Autumn Virginsbower, this non-native invasive species was originally introduced as an ornamental but has since escaped cultivation. It is reported to be invasive in at least 10 states, including South Carolina. You’ll often find it invading forest edges, rights-of-way, and the edges of disturbed areas.
Clematis (terniflora) blanketing roadside vegetation on Spring Street in Darlington, SC.
Terasa M. Lott, Clemson Extension
It may be hard to resist, but you should not be tempted to add this plant to your landscape. It is a vigorous grower that will blanket other vegetation, reducing sunlight penetration. The many seeds produced are dispersed by the wind, meaning new plants can pop up all over the place, changing the composition of the local plant communities.
If Sweet Autumn Clematis is already residing on your property and you’d like to remove it, please refer to the UF/IFAS Center for Aquatic and Invasive Plants.
The good news is there is a native species with nearly identical flowers. You can distinguish the two species using the margins (edges) of the leaflets. The leaflets of the non-native Clematis terniflora have smooth margins, while the leaflets of the native Clematis virginiana have toothed margins.
Smooth margins = Clematis (terniflora) (non-native invasive).
Terasa M. Lott, Clemson Extension
Toothed margins = Clematis (virginiana) (native).
Wendy VanDyk Evans, Bugwood.org
For more information on Clematis species suitable for South Carolina, see HGIC 1104, Clematis.
