The previous occupant of our house was obviously a keen Clematis cultivator. I feel a twinge of guilt when I recall the specimens we sacrificed whilst removing the rampant Russian Vine from the trellis around our decking, and the others that bit the dust when the boundary fence blew down.
Half a dozen or so still remain, and they’re looking pretty spectacular at the moment. However, like a number of plants in my own garden, they’ve been somewhat neglected and the time has come for me to sort out what should be done, and when to do it, for each clematis.
Clematis fall in to three pruning groups, based on when they flower. Those in groups two and three need regular pruning otherwise they produce long, bare stems, with all the flower interest at the top.
Clematis Pruning Group 1: Early flowering
This group flowers on shoots produced the previous season, and includes the well-known and vigorous Clematis montana. Group one clematis don’t generally need regular pruning; just the removal of dead, diseased and damaged wood, but if they are overgrown or out of control, prune to shape in mid to late spring, after flowering. My Clematis montana is not long past flowering so this is going on my to-do list for the weekend, before it engulfs my other, slower growing climbers.
Clematis montana - a group one clematis
Clematis Pruning Group 2: Mid-season flowering
Group two consists of large-flowered varieties that bloom during May-June on the previous season’s growth. I’m quite fond of the pink striped cultivar that I’ve inherited, which I think is probably Clematis ‘Nelly Moser’. For group two clematis, lightly prune in the summer, after the first flush of flowers. Smaller flowers will then be produced on the current season’s growth.
Then, in late winter / early spring, aim to establish a framework of older wood and stimulate new growth by removing weak shoots, thinning congested growth, and cutting about a fifth of the oldest stems to 30cm above the base.
Clematis ‘Nelly Moser’ - a group two clematis
Clematis Pruning Group 3: Late-flowering
Group three clematis are great additions to any garden in order to extend the flowering season; they flower from midsummer through to autumn on wood produced during that same season. I have what I believe to be a beautiful blue Clematis ‘Perle d’Azur’, but I can see already that my failure to prune it properly this winter has resulted in it becoming a bit top-heavy.
For Group three clematis, prune in late winter or early spring (Feb, or early March for us northerners), as the buds begin to show signs of breaking. Prune the stems back hard to the first pair of leaf-buds on the stem, which will be about 15-30cm above soil level. This will stimulate the breaking of dormant buds near the base. It looks pretty brutal, but it’s the way to go, honest!