How to prune -the kindest cut
by Drucilla James
Pruning often seems a rather daunting mystery. Cutting off too much from a plant can appear worryingly irrevocable, while cutting too little probably misses the point. And yet pruning is a skill that must be mastered, particularly in the small garden, if plants are to look their best and keep in scale with your space. Our simple guide explains what to do at this time of year. Look out for future features which will tell you what to do next as the seasons unfold.
Pruning encourages more prolific flowering, fruiting and colourful stem production and also helps create more compact and bushy plants. What’s more, plants pruned to finely sculpted shapes, can form strong focal points in the garden.
Remember, when you prune, it is important to decide on the final shape you want to create. As each pruning cut is made, stand back and judge whether you are achieving the desired effect.
Key plants for spring pruning
- Shrubs with colourful winter stem interest such as dogwoods
- Roses, including climbers
- Clematis groups 2 and 3 – see http://www.cityplanter.co.uk/practical/how-to/how-to-prune-clematis
- Shrubs that flower in winter on last year’s new stems such as Corylopsis pauciflora, Hamamelis (witch hazel), Deutzia
- Perennial border plants such as Phlox
Things you’ll need
- A pair of secateurs – buy the best you can afford as they will retain a very sharp edge which will give clean cuts and reduce the risk of introducing disease.
- A pair of loppers – these are needed if you have thick branches to deal with.
Different pruning cuts step-by-step
Cutting to opposite or alternate buds
Cutting the stem above a bud stimulates hormone production and so brings about the growth of the bud to form a new stem. So it is important to be able to identify buds along the stem of the plant you are going to prune. Their shape and size can be very variable but in general they appear as slight swellings or bumps and are formed where leaves are growing or where there is a leaf scar (a mark on the stem where last year’s leaf has dropped off).
Where buds are arranged as a pair opposite each other, the stem needs to be cut flat above the buds.
Where buds alternate, the cut needs to be just above the bud and sloping away from it.
Pruning to new growth
Old stems which tend to be more ‘woody’ can be cut back at an angle just above a new fresh stem.
Some plants can be pruned quickly and effectively by cutting off the tops using sharp shears.
For some young plants, the soft growing tips can be pinched out to encourage new side branches and to develop a more rounded-shaped plant.
Examples of pruning cuts applied to particular plants
Cutting to buds: Hydrangeas, Cornus and Daphne
- Hydrangea paniculata grandiflora flowers in late summer on stems produced that year. Pruning last year’s growth promotes new flowering wood and results in larger flower panicles. Prune to one or two buds from the base of the stem and create an open framework. Hydrangea macrophylla (Mop head) flowers in summer from buds formed the previous summer. In late spring, after the frosts have finished, prune the stems back to a healthy pair of buds. Avoid pruning too much as there is a risk of removing too many of the flower buds.
- Cornus (Dogwood). Cut out all the dead, thin, weak and diseased stems. Prune the strong stems back to the first pair of strong healthy buds by making a straight cut across just above the buds.
- When Daphne matures, long growths will appear at the end of the main stems and these can be cut back by 20 cms using sharp secateurs. The cut should be made above a leaf bud and angled slanting away from the bud. This will result in increased flower production. (See above).
Pruning to new growth: Hamamelis (witch hazel), Corylopsis and Deutzia
These beautiful plants for the small garden can become too large, so need to be pruned; this also helps create a more attractive shape. Prune them just as the flowers are fading cutting back the taller branches by up to 50 cms. Remove old stems and leave new healthy branches.
Shearing: Heathers, lavenders and border perennials
- Heathers and lavender can be pruned using sharp shears to cut the young stems just above the old woody stems leaving short lengths of the young green shoots. Don’t cut into the woody stems as these do not re-grow.
- Some border perennials when they have grown to about 30/40 cms during the growing season can be cut back by a third. This will create bushier, more compact plants which will require less support later in the season and they will also flower more profusely. The whole plant can be cut back or only some selected stems and the rest left, which will allow the stems left to flower before those cut back, and extend the flowering period of the plant. Cut stems with secateurs and the whole top of the plant using sharp shears. This latter procedure is often referred to as the ‘Chelsea Chop’ and can be used in the late spring for plants such as Phlox, Sedum, Helianthus and Rudbeckia.
With the young plants, pinch out the soft green tips to form a bushy plant.