Fall Clematis Lookalikes

 

I’ve written about native clematis before. For the most part, native clematis look like small bells; a friend used to call them American bells. You can read my earlier post about native clematis here. One clematis, however, is different and its difference leads to confusion with a very similar non-native species; both species are both blooming now.

Clematis virginiana, native

Clematis terniflora, not native

These two clematis species are so similar that I can’t tell them apart by the flower alone. The native species is known as virgin’s bower (Clematis virginiana). The non-native species is known as sweet autumn clematis (Clematis terniflora, also called C. paniculata). Each of them has small, open white flowers with four white petals. Their growth habit is similar and both can be found this time of year flowering profusely on roadsides where they have scrambled above shrubs and perennials to create a snowy, white blanket.

It is the foliage that we must look for when identifying the species of these similar plants. Each species has compound leaves with 3 leaflets (occasionally the non-native may have 5 leaflets and there may be some whitish stripe on the leaflet). The leaflets of the native species have toothed edges (also called dentate) while the leaflets of the non-native species have smooth edges (also called entire).

Clematis virginiana seedheads

Clematis terniflora seedheads

I also find that the seedheads of the native species are much showier, apparently because it has more carpels. See photos above.

You may ask why it matters which one we grow when they look so much alike. I could find no research about which one bugs prefer, either for nectar or for foliage (as a host plant). Given there is still so much insect interaction still unstudied, I prefer to cultivate the native one in the hope that it offers a slight advantage over the species which only recently arrived.