July Vine of the Month-Clematis
We have talked about some aggressive, problem vines on Garden-Lou:
-Kudzu October Anti-Plant of the Month-Kudzu –
-Trumpet creeper September Perennial of the Month-Trumpet Creeper –
-Climbing hydrangea May Vine of the Month-Climbing Hydrangea –
So how about a friendly, well-behaved vine for a change?
First, why do we usually want a vine? Usually, to climb a structure like an arbor, fence, or wall, and maybe to provide height or a vertical element in a garden design. But most vines will just keep going and become a huge maintenance issue that ends up requiring a pro to remove.
Enter clematis-NOT sweet Autumn clematis (LINK) but one of the many cultivars that are well-behaved and come in a range of colors and forms. Sounds like an easy choice for your mailbox or trellis, but after planting, things get complicated…pruning.
Of the over 250 species of clematis and the numerous cultivars available, most fall into three main groups with unique pruning times;
Group 1 – Spring bloomers. Flower only on old wood from the previous year. These are pruned after spring flowering. This includes cultivars like ‘Apple Blossom’, ‘Snowdrift’, and ‘Bluebird’.
Group 2 – Repeat bloomers. Flowers on both old and new wood. These can be cut to the ground or pruned in fall or spring, but flowering will be reduced or delayed. These include ‘Crimson King ’ and ‘Étoile de Paris’,
Group 3 – Fall bloomers. Flowers only on new wood. Can be cut to the ground in fall or early spring before new growth emerges. This group includes sweet autumn clematis and the common ‘Jackmannii’ cultivar. To make things even more complicated, ‘Jackmannii ’ can be pruned like Group 2 or 3.
Okay, so no problem, right? Just pick the corresponding group and be done. The problem is that when you buy a clematis at your local nursery or garden center, RARELY does the plant tag include what group your new plant-baby belongs to. Even rarer is the staff that can tell you which group the cultivars they are selling belong to.
We come back to that word-RESEARCH! A quick Google search should solve your problem, but if you do not have the botanical/cultivar name for your clematis, it might be safer to just let it go for a year and note when it flowers, otherwise risk a season without blooms.
Group 2 seems to be most confusing for people. It’s best if you prune in late winter or early spring (February) and after the first flush of flowers in early summer.
Both ‘Samaritan Jo’ (left) and ‘Jackmanii’ (right) belong to Pruning Group 2.
Whoa, you say, that’s getting too complicated. Why prune at all?
Because if young clematis are left unpruned, they often produce very long single stems and only flower at the very top.
A common practice for newly planted clematis is pruning them back hard the first spring after planting. Cut back to just above a strong pair of leaf buds about 12” above soil level. This will encourage multiple stems, which can be trained into supports to give good coverage. If you have inherited a mature clematis vine that has gotten out of control or looks scraggly, this is also a way to get it back in line.
Clematis prefer full sun, but with shaded roots. Some cultivars do better in part shade than others, so research carefully before you buy. Keep the roots shaded with a rich, organic mulch like compost and/or other plants around the base.
Rich, well-drained organic soils are preferred, but do not let them dry out. A little afternoon shade can help with scorch in the St. Louis area.
What I love about this plant;
-Zillions of cultivars and species to pick from.
-Colorful, showy flowers, usually ranging from white to pink, red, and purple.
-Showy seed structures.
-Better behaved than larger, aggressive vines.
-Great for smaller gardens, balconies, mailboxes, trellises, or arbors without causing damage.
-Deer resistant and black walnut tolerant.
What’s not so great;
-Not all clematis are well-behaved-BEWARE sweet autumn clematis; September Anti-Perennial of the Month-Sweet Autumn Clematis –
-Stems can be brittle, so use care when training and maneuvering stems.
-Although there are some shorter, clump-forming clematis, the most commonly sold are climbers and will need a support to climb on, such as a trellis or arbor.
-Clematis climbs by “twining” around a support and might need help to cover your mailbox or fence with mono-filament (fishing line), which gives an invisible support. Make sure to tie small knots every few inches to help it hold on and prevent it from sliding back down the line.
-Susceptible to wilt/stem rot, which can be fatal. Powdery mildew, leaf spots, rust, and assorted viruses can be issues. Spider mites, aphids, vine weevils, slugs/snails, scale, and earwigs can be occasional visitors.
-Comments or questions? Email Garden-Lou at gardenloustl@gmail.com
Words and photos by Jo Batzer
© Jo Batzer, garden-lou.com-2026, All rights reserved.
