When shrubs are grown for their spring flowers, they require different timing and technique to “ordinary pruning” (if there is such a thing). For the purposes of this article, I have presumed that the shrub is not in need of major restorative pruning, nor newly planted.
Firstly, questions regarding pruning generally: –
- Why?
- When?
- How?
Regarding larger shrubs: –
- Is there a Tree Preservation Order?
- Is this a Conservation Area or National Park?
- Is the shrub too large to safely prune by myself?
- Can I prune only using hand tools?
The former may require special permission. The latter relate to health and safety; it may be a two person job, require special training, or need the area to be fenced off from the public.
Plus: –
- Does the shrub bear edible fruit?
- Is it part of a hedge, with birds nesting, or a wildlife habitat?
- Do you want a formal or informal look?
And my favourite: –
- Does the shrub need pruning?
Certain shrubs rarely do, for example, Cotoneaster.
Tips:
Some gardeners may find it helpful to colour code shrubs to remind them when they should be pruned. Particularly useful where there are less qualified staff, apprentices and volunteers.
Spring flowering shrubs, are usually considered to be those which bloom March – June. Those which bear edible fruits and berries are treated differently and not covered here.
Why Prune?
To –
- increase / maintain good flowering show next year
- maintain the shape of the shrub
- improve the overall shape, perhaps where it’s become to big for its allotted space
- and importantly, to remove dead, diseased or dying stems
When?
The fundamental rule is to prune after flowering to allow next year’s flowering shoots to grow.
This is because spring flowering shrubs bloom on the growth they made after flowering the previous year. For example, Forsythia, Philadelphus.
How?
Have a look at the shape. Is the growth predominantly rising from the base with a group of long shoots that terminate in flowering stems? Are they upright or arching? Or does the shrub have fewer shoots near the base but more branching stems with flowers?
Pruning, like drawing, requires a lot of observation. Ornamental spring flowering shrubs may be grown primarily for their blooms, but for most of the year what is on show is foliage (summer and autumn) and stems (winter). Therefore, the shape of the shrub is an important consideration.
Firstly remove dead, diseased and dying stems. Then step back and examine the size and shape of the shrub. There may be a mix of shoots with spent flowers and non-flowering ones.
Now comes the part which is either really easy or a bit tricky. Without seeing the shrub, and knowing the wide variety, not just of types but the way they grow when left unpruned, it is difficult for me to be definitive in exactly what you prune off. Where I can be decisive is in saying, if you’re really not sure, ask! Reasonably confident? Carry on but don’t get carried away.
When pruning back to a bud, you have two options. Where there are two buds opposite each other on the stem, make a horizontal cut. Where the buds grow alternately up the stem, find one heading in the desired direction for new growth and cut at the same angle. Both types of pruning cut should be approximately ½ cm above the bud.
Shoots with old flowers may be cut back to a healthy bud. This gives a good shape on the wider branching shrubs. For younger plants and those needing minimal pruning such as camellias, this may be all that is needed. Where growth is predominantly from the base, just do a few for ‘tidying up’ purposes.
Where the shrub has tall stems and arching stems emanating mainly from the base, then take out some of the older stems in their entirety. This is not coppicing, as might be carried out on Cornus, as not all the stems are removed. Up to a third of the shoots can be removed, depending on the size and health of the shrub; pruning out the oldest first as these are the least productive. Cut to 2 -3 buds from the base. This will encourage new shoots for flowers next spring.
Wall Shrubs and Climbers
Wall shrubs are generally pruned as above if they’re spring flowering. For example, Jasminum nudiflorum, winter flowering jasmine.
Spring flowering climbers – Clematis is the main one and one which is simple to do (despite many gardener’s fears). Clematis fall into three main groups for pruning. Check the label or observe it – when does it flower? Group 1: early flowering; prune mid to late spring.
Little regular pruning needed. They may need thinning out when older; if so, prune to 15cm from the base. Heavy pruning will reduce flowers.
Pruning Spring Flowering Trees, Fruit Trees
The majority of trees which are grown for their decorative spring blossom are deciduous, for which the general rule is to prune them when they’re dormant. However, its not quite that simple, particularly where fruit trees are concerned. This topic is better covered in separate articles.
Hedges
Hedges may contain spring flowering shrubs. Although some of the above tips are relevant, the shrub needs to be considered as part of the whole hedge.
Pruning should take into account nesting birds. It is an offence under the Wildlife & Countryside Act 1981 to damage or destroy the nest of any wild bird while it is in use or being built. As the bird nesting season is usually considered to run from March to August, you can perceive there may be issues with pruning spring flowering shrubs within a hedge. This topic is best considered as part of hedge maintenance.
Pruning Tools
A brief note for novices about types of hand tools.
Secateurs
Bypass secateurs (scissor shaped) for best cutting living stems and branches as they give a sharp, clean cut.
Anvil secateurs are best for dead wood, or where a slight crushing of the stem doesn’t matter.
There are also long handled secateurs for reaching into dense shrubs with fairly slim stems.
Loppers
Loppers are basically secateurs able to cut larger diameter branches and stems; they have a longer handle and have a two handed action.
They often have a ratchet motion which gives greater cutting power to your wrists. Loppers may have elbow length handles or be extendible to reach into lower tree branches.
Saws
Saws come with different grades of cutting teeth: the larger the branch, the coarser the teeth should be.
A Pruning saw has a slightly curved handle which makes reaching into the shrub or tree much easier than with a straight saw.
Pruning knives are similar shape, but smaller. They’re also used to gather material for vegetative propagation.
Do check out related articles, by myself and others. If we haven’t written them yet, you can be sure they’re in process!
Plews Garden Design and Consultancy