Clematis: What's new + Planting, Support & Pruning

Do you ever find yourself questioning the information you read about plants? So often I have read that Clematis like their heads in the sun and their roots to be in cool shade. Where did that little gem of wisdom come from anyway? Is it something that some plant expert said once and gardeners like myself just pass along?

When you stop and think about this little nugget of information, it makes good sense. Most vines stretch up out of shady undergrowth to reach for the sun. Clematis are no exception. They like their top growth to receive six hours of sun, while the base of the plant is shaded by other plants. To have success with them, all you need to do is keep this preference in mind.

 Clematis also like fertile well-drained, somewhat alkaline soil. If you are planting a clematis for the first time this spring, remove the plant from the pot and soak it in a shallow pail of water for 10-15 minutes before planting. Place a generous layer of well-rotted manure or compost at the bottom of your planting hole. Plant it deeply: the top of your Clematis's root ball should be placed about 5 cm (2.5 inches) below ground level. Back fill the hole with soil that has a generous amount of compost and a few handfuls of bone meal. Water thoroughly and frequently until your Clematis is established.

Clematis are a popular choice for so many reasons. They have diverse flower forms and colors. They can be grown on walls or fences, up tree trunks or through climbing rose bushes. Some cultivars are quite vigorous, but they aren't vines that is hell-bent on taking over the world. It is also possible to find a Clematis that will bloom in just about every month of the growing season.

What's new in the world of Clematis?

Patio Clematis! These are compact vines were bred by famous English nurseryman Raymond Evison to grow to a height of just five to six feet. 

Unlike the traditional Clematis, which bloom at the end of each stem and side branch, these vines bloom on all leaf axils all the way down through the plant. These new cultivars are heavy feeders, so use a slow-release fertilizer following the manufacturer's instructions. Prune these new Patio Clematis to 12 inches above soil level in spring.

I have several of these shorter Clematis and have really come to love them. 

Most of the fence running the length of our backyard is too shady for Clematis, so up until now I have been rather limited in the number of Clematis I have been able to grow.

The new shorter heights have allowed me to place Clematis out in my sunny flower beds on simple supports like this tomato cage. 

This white Clematis 'Hyde Hall' was just gorgeous last May.

Pruners at the ready a nervous gardener stands before the thin brown tangle of clematis vine in early spring. It flashes into her mind that there are three main groups of clematis vines, all needing specific regime of pruning. The plant tag, that might have helped her identify the clematis in question, has long since gone the way of the Do-do. 

What happens if you do nothing and don't prune a Clematis?

A Clematis that has been neglected may still flower, but it will produce fewer blooms than it would have if it received appropriate care. They can also get leggy with all of the new growth and flowers coming near the top of the plant. Pruning a Clematis stimulates strong new growth. It also clears the tangle of stems allowing air to circulate lessening the chances of wilt and other problems.

The first thing our anxious pruner needs to do is not to stress. It sometimes worries me that more people are so terrified of making a mistake, they don't garden at all. Gardens are actually quite forgiving. If you get your pruning wrong, you might go without Clematis flowers for the growing season, but there is always the promise of next year.

If you are uncertain about the variety of clematis, hold off pruning for the summer and note when your clematis blooms. The bloom time will help you identify when it is appropriate to dig out those pruners.

The Three Pruning Groups:

Group 1: 

Clematis that bloom in early spring, do so on the previous years growth. Do not prune a Clematis that blooms in early spring until after it flowers. Pruning it after it flowers will encourage new stems that will carry next spring's flowers.

Some Group 1 Members: C. alpina, C. macropetala, C. montana

Group 2:

These Clematis bloom in early summer on the previous season's growth and sometimes later in the season on the current season's growth. Remove all dead or weak stems in March (April here in Ontario). Then prune the entire plant by about a third (approximately 25cm above ground level). Look for a healthy green bud and make your cut above it.

Some Group 2 Members: 'Bees'Jubilee', 'Henryi', 'Nelly Moser', 'The President'

Group 3:

This final group produce flowers in the late summer and fall. These Clematis bloom on new growth each year and are easiest to prune. Cut back all vines to 30 cm (12 inches) high each spring.

Some Group 3 Members: 'Ville de Llyon', Perle d'Azur', 'Jackmanii', C. viticella, C. texensis.

Clematis in a private garden in Niagara-on-the-Lake. Isn't it gorgeous?

What happens when you don't support a clematis properly? 

It can flop over on itself. I can speak to this from experience. There is a purple clematis by my front door that is in desperate need of better support. Fixing the issue is high on my spring to-do list.

Clematis in a private garden in Mississauga, ON

This is a perfect example of a clematis that has flopped. It looks pretty, but the growth underneath the fallen top section of the vine won't get any light or air circulation. You may get away with this, but you run the risk that the delicate stems will snap and break in the wind. 

Most of the cultivars you'll find at your local nursery will grow to 8-15 ft, but some Clematis vines can reach a height of as much as 20-30 ft. Check the plant label before you make your purchase.

The Clematis on the front picket fence.

I purposely allow this bell-shaped purple clematis to fall forward and drape over the picket fence in my front of the garden.

My clematis shoots straight up and looks a little silly when it sticks up over the top of the fence each June. Gradually I bend it forward over the white pickets, so the somewhat fragile stems don't break.

If you want a clematis to cover a fence, you will need to provide some extra support. On the left, a metal trellis sits in front of the fence. On the right, eye hooks hold a wire grid in place.

Private garden Niagara-on-the-Lake, ON.

I thought that his was a rather interesting way to deal with a Clematis that grows higher than a typical fence. 

This Clematis is supported with a wire grid and is espaliered along the length of the wire. All Clematis has woody stems that are quite brittle. To replicate this you would have to encourage any fresh green shoots to spread out horizontally down the length of the wire.

The Toronto Botanical Garden's Trial Garden

It you have one of the newer Patio type of clematis, a pretty obelisk might be all the support you need.

Private garden, Mississauga, ON.

I thought that this was a novel idea. There is no fence between these two neighbouring properties, so to create a bit of privacy a partial fence was constructed with a couple of fence posts and 1x2's laid in a grid. As a finishing detail, the whole thing was stained grey. 

Sadly the view of the Clematis vines are not equally splendid on both sides. The side you are looking at here is in shade. The two vines favour the sunnier side of the fence, which can be seen in the next image.

Birdhouses in Donna's garden in Halifax, N.S.

In my friend Donna's garden, Clematis clamour up the poles of two birdhouses.

Donna tells me that, "Eye hooks are fastened to the four corners of each birdhouse and two eye hooks are placed at the bottom of each post. Then wire is strung from the four corners to the bottom of the pole. This seems to work well for us."

As a final word, it worth mentioning that the seed heads of Clematis can be quite ornamental. Their fuzzy pompoms can be almost as pretty as their flowers.