Time for drastic pruning

9:09am Friday 27th June 2008

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PRUNING is a scary subject for some gardeners. There are so many different techniques that can be used for keeping the shrubs and climbers in our gardens in shape (the RHS Encyclopaedia lists 13 pruning groups), that even professional gardeners have to consult their textbooks from time to time, before embarking on a job.

Small wonder then that amateur gardeners should be daunted by the task of pruning a large shrub or rampant climber.

So why do we prune woody plants at all, why not just leave them to get on with it?

Well - by removing dead, diseased or damaged wood, regular pruning maintains a healthy plant and encourages the formation of new growth. Pruning should maintain a shape and structure that displays the plant to its best advantage and it should encourage the production of flowers and fruit.

In gardens where space is limited, pruning can also be used to restrict the size of a woody plant.

As a rough guide to the best time to prune, you can’t go far wrong by pruning just after a plant has flowered, effectively giving it nearly a whole year to recover before it will need to flower again.

I always attempt to make my pruning as ‘invisible’ as possible, hoping the finished article will look as natural as if it hadn’t been touched. Occasionally, however, the best solution is to cut the plant right down to the ground and let it start afresh.

I resorted to just such a solution this week, when I had to deal with an old Forsythia that had partially fallen over under the weight of its unpruned branches. I had a go at ‘invisible’ pruning but when I’d finished the remaining branches looked so thin and spindly that they had to go too! Cutting a plant down to ground level is not a technique for the faint hearted. A shrub pruned this drastically must now adhere to the ‘two chances’ principle – it can either live, or it can turn up its toes and die of shock. Look on the bright side - if it lives, you will have a shrub with a new lease of life that can be more correctly pruned in future. And if it dies, then you’ll have a good sized planting space for some new shrubs.

Sometimes there are little clues that indicate this technique will be successful. Look for buds or new shoots appearing at ground level or near the base of the plant. Leave these intact when you prune, and the plant will have a head start on the road to recovery.

An overgrown Clematis macrocarpa in our back garden obligingly produced some such shoots a few weeks ago and gave me the excuse I needed to cut the rest of the overgrown climber to ground level. The new shoots are now growing away strongly - they might even mature quickly enough to give me a few flowers next spring.

Jobs for this week...

Having planted out the summer bedding, it’s already time to think about next winter and spring! Sow hardy annuals like wallflowers and Brompton stocks in trays for planting out in the autumn.

Support crops of peas with netting or small, brushy hazel twigs, stake climbing and runner beans with a stouter framework of canes or hazel poles.

Keep greenhouses and conservatories well ventilated; water in the cool of the early morning or evening to avoid leaf scorch and pots drying out too quickly.