Clematis Pruning

Pruning Group A  -  Pruning Group B  -  Pruning Group C

Clematis can live up to 50 years.  Proper pruning, typically done in the spring, can ensure your long-term investment.

The mere thought of pruning a clematis strikes fear into the hearts of even seasoned gardeners. Well, take heart, it's not that complicated and incorrect pruning is rarely (if ever) terminal. The worst that can happen is that it doesn't flower for a year. As far as pruning requirements are concerned, clematis can be divided into three groups; A, B or C.

PRUNING A YOUNG CLEMATIS

I cannot stress too much that proper pruning of these young plants is absolutely critical for their future growth and development. All too often I have seen a perfectly good little clematis which has been planted out and allowed to develop one very long, spindly growth. And the owners have complained that either it's a weak plant or it doesn't flower well when the only real problem is how it's been treated.

A plant like this will take years to develop properly if it ever does.  Roots and top growth need to develop proportionately. Top growth needs to be restrained until root growth is sufficient to support it. To do this, the clematis should be kept pruned back to a height of roughly 18"-24" the first year regardless of its pruning code.

This will also encourage both branching and the development of multiple stems from the buds under ground. This is particularly important for group B clematis which are notoriously reluctant to fatten up at the base. Two or more years of this treatment may be necessary for the plant to develop a satisfactory framework, but the rewards in terms of future flowering and general appearance are well worth it. During this time flowering is not sacrificed, rather delayed until later in the season.


Late season pruning of clematis is not recommended in areas which experience cold winters.  Any unexpected warm spell will encourage new growth which will certainly be killed by the cold spell that follows.  So resist the temptation to tidy up the clematis tangles in the fall...wait until Spring.


PRUNING GROUP A - Back

A. Light pruning to remove dead bits.

These will flower on "old wood"- i.e., previous season's growth. This group includes montanas, alpinas and macropetalas and some large flowered hybrids such as Miss Bateman, General Sikorski, H.F. Young, Mrs. Cholmondeley, etc. These are the earliest clematis to flower (May-June for us in the North East, earlier in milder areas). Light pruning to remove any dead bits and neaten it up is all that's needed. (See diagram). If after a hard winter some stems appear dead, wait until the leaves are emerging on the rest of the plant and then prune slowly in sections, one stem at a time, from the top so as to avoid the premature removal of what is actually live wood. (I learned this the hard way!)  If you have a Montana which has outgrown its allotted space and is in a terrible tangle, you can control it by pruning hard immediately after flowering. This will allow plenty of time for it to put out new growth which will in turn flower next spring. If you wish, you can take it right back to the old woody stems which were originally used to attach it to the supporting structure.

Do wear gloves when pruning clematis as the brittle wood splinters easily under attack.


Upon concluding a pruning session it is a good idea to feed with a good all-purpose fertilizer and lime as needed.  If your soil is deficient in phosphorus, sprinkle around a handful of superphosphate.


PRUNING GROUP B - Back

B. Cut out dead growth and weak shoots to a strong pair of buds.

This group is the one that drives people crazy! It will flower on both old and new wood and includes clematis whose most prolific blooming is in the spring (early to mid-June here) with a more modest show in the fall.

Proper pruning will do much to ensure a spectacular display.  Basically you want to prune lightly, removing dead and weak wood first so as to get a better view of the plant.  Remember that the largest flowers will be produced on old wood, so you don't want to remove too much.  Prune slowly from the top until you reach a good bud, one stem at a time (See diagram).  If the stems are growing together in a jumble, this is the time to carefully untangle by cutting the old leaf petioles to sever the stems from the support.  Spread them out and reattach with twist ties.  As the new growths emerge in the spring you can train them as you wish.  If and when a "B" clematis has outgrown its space and it needs remedial pruning or rejuvenation, meaning a hard cutting back, this can be accomplished after the spring flowering and still leave plenty of time for the new shots to mature for a good fall display.  Admittedly, some varieties (Will Goodwin and Henryi spring to mind) make it difficult to pin-point precisely when this first flush is over as they never really stop flowering. You will simply have to steel yourself to do the job:  consider the greater good and chop the budded stems back by 1/3 or more as necessary.

If for whatever reason - perhaps a trip abroad or a family wedding - you want the heaviest flowering to be late in the season rather than early, you can accomplish this simply by pruning hard in the spring.

However, bear in mind that the double-flowered varieties carry the double crop on old wood, so that hard pruning will result in single flowers only.  Some varieties, however, such as Vyvyan Pennell and Beauty of Worcester, like to surprise us with the occasional double bloom on new wood in summer and many of the newer hybrids such as Multi-Blue and Arctic Queen are double on old and new wood.


PRUNING GROUP C - Back

C. Cut back hard in early spring.

Be ruthless here! Ignore the fat buds you see further up the stem, grit your teeth and cut back to a height of roughly 8"-12" (this should include 2 strong sets of buds. See diagram). Do --this and you will be rewarded by the emergence of vigorous new shoots from the base which will result in a nice, full, multi-stemmed plant loaded with flowers. As the shoots grow you will of course want to spread them out so as to make the most of the display. Sometimes the plants are obliging and train themselves, but most often they need a firm guiding hand.

Always be sure to clean up pruning and dead leaves by putting them in the trash, never the compost.  

 

 

Remember, a well-trained clematis, like a well trained dog, is a joy to behold.
 

   
┬ęClematis Nursery, All rights reserved