RHS Pruning Group 1: Light Pruning of Trees and Shrubs
RHS Pruning Group 1 covers trees and shrubs that naturally develop an attractive, well-branched framework and generally require very little routine pruning.
These plants are usually at their best when allowed to develop naturally. Excessive or unnecessary pruning can spoil their shape, remove flowers and reduce their ornamental value.
The basic principle of Group 1 is:
Prune only when necessary and preserve the plant’s natural form.
What Is RHS Pruning Group 1?
Group 1 is primarily concerned with maintaining a plant’s health, structure and appearance rather than cutting it back every year.
Pruning is normally limited to removing:
Dead branches
Damaged or diseased wood
Crossing or rubbing branches
Weak or badly positioned growth
Unwanted suckers
Congested stems
Branches affecting access or safety
If the plant is healthy, attractively shaped and growing comfortably within the available space, it may not need pruning at all.
Which Plants Belong to Pruning Group 1?
Group 1 generally includes free-standing deciduous and evergreen trees and shrubs that naturally produce an attractive framework.
Examples include:
Acer palmatum – Japanese maple
Amelanchier – snowy mespilus or serviceberry
Arbutus – strawberry tree
Cornus kousa – flowering dogwood
Hamamelis – witch hazel
Ilex – holly
Laurus nobilis – bay
Magnolia
Rhododendron, including deciduous azaleas
Syringa – lilac
Pruning requirements can vary between species and cultivars. Always identify the particular plant before carrying out substantial work.
If you are choosing a new ornamental tree, explore our collection of specimen trees, available with professional planting across North West England.
How to Prune Group 1 Trees and Shrubs
The objective is to improve the plant selectively without dramatically reducing its overall size or forcing it into an artificial shape.
Before making the first cut, stand back and inspect the complete plant. Identify which branches genuinely need removing and consider how each cut will affect the overall framework.
Remove Dead, Damaged and Diseased Growth
Start by removing branches that are dead, damaged or showing clear signs of disease.
Cut back to healthy wood or remove the branch cleanly at its point of origin. Do not leave unnecessarily long stubs.
Clean tools before moving between plants, particularly when disease may be present.
Remove Crossing and Rubbing Branches
Where two branches cross or rub together, retain the stronger and better-positioned branch.
Repeated rubbing can damage the bark and create an entry point for disease. Removing one branch at an early stage is preferable to waiting until both become damaged.
Thin Congested Growth
Lightly thin areas where too many branches are competing for the same space.
The purpose is to improve the structure of the plant while retaining its natural character. Avoid removing excessive amounts of healthy growth in a single session.
Branches growing directly towards the centre of the canopy can be removed where they are causing congestion.
Remove Badly Positioned Growth
Remove shoots that are growing in an unwanted direction, interfering with another plant or obstructing a path, entrance or important view.
Where possible, trace the unwanted branch back to its point of origin or a suitably positioned side branch rather than simply shortening its end.
How to Make the Correct Pruning Cut
Use clean, sharp tools appropriate to the thickness of the branch:
Secateurs for smaller shoots
Loppers for thicker stems
A pruning saw for larger branches
Smaller stems can be shortened immediately above a healthy outward-facing bud or removed back to an appropriate side branch.
When removing a complete branch from a tree, avoid damaging the slightly swollen branch collar where it meets the trunk or parent branch. Do not make a completely flush cut against the trunk.
Larger branches should be removed carefully and in stages to prevent their weight from tearing the bark.
Pruning large trees, high branches or structurally significant limbs may require a qualified arborist.
When Should Group 1 Plants Be Pruned?
For many Group 1 plants, light pruning can be undertaken during late winter or early spring before strong new growth begins.
This timing makes the structure of deciduous plants easier to inspect. However, there are important exceptions, and the correct timing depends upon the particular species.
Trees That Bleed Sap
Some trees can lose significant quantities of sap when pruned during late winter or early spring.
Japanese maples and birches are among the plants that can be prone to bleeding. Necessary pruning is generally better completed when the plant is in full leaf or during late summer, depending on the species.
Magnolias
Deciduous magnolias generally require very little pruning. Where pruning is necessary, it is commonly undertaken during midsummer or late summer once the leaves have fully expanded.
Substantial pruning can cause vigorous regrowth and may spoil the plant’s natural framework, so renovation should be approached cautiously.
Lilacs and Deciduous Azaleas
Spring-flowering plants such as lilacs and deciduous azaleas are normally pruned after flowering.
Pruning immediately before their display could remove flower buds and substantially reduce flowering for that year.
Dead or Dangerous Branches
Dead, damaged or obviously dangerous branches can normally be addressed when they are discovered. However, extensive work should still be planned around the needs of the particular species.
Should Group 1 Plants Be Pruned Every Year?
No. Group 1 does not mean that every listed plant requires annual pruning.
Inspect the plant and ask:
Is there any dead or damaged growth?
Are branches crossing or rubbing?
Is the plant becoming congested?
Is it affecting access or safety?
Is it outgrowing the available space?
Would pruning improve its health or structure?
If the answer to all these questions is no, leaving the plant alone may be the best choice.
Looking After the Plant Following Pruning
After pruning:
Remove all cut material from around the plant.
Water if the soil is dry.
Maintain a weed-free root area.
Apply an appropriate organic mulch where required.
Keep mulch away from direct contact with trunks and stems.
Monitor the plant for signs of stress, pests or disease.
Newly planted trees and shrubs should normally be allowed to establish before unnecessary pruning is undertaken. Read our guide to looking after newly planted trees and hedging for establishment advice.
Common Group 1 Pruning Mistakes
Pruning Simply Because It Is Spring
Group 1 plants do not automatically need annual pruning. Inspect the plant first.
Cutting Every Branch to the Same Height
This destroys the plant’s natural structure and can produce a dense outer layer of unattractive regrowth.
Removing Too Much at Once
Heavy pruning can place unnecessary stress on a mature tree or shrub. Substantial renovation is often better spread across several seasons.
Pruning Spring Flowers Before They Bloom
Pruning plants such as lilacs before flowering removes the buds carrying that year’s display.
Ignoring Species-Specific Timing
Japanese maples, magnolias and spring-flowering shrubs may require different pruning times even though they are all included within Group 1.
Other RHS Pruning Groups
Group 1 is intended for trees and shrubs requiring minimal intervention.
This is very different from RHS Pruning Group 5, where established shrubs are cut back hard after flowering to encourage vigorous replacement stems.
Early-flowering evergreen shrubs may instead belong to RHS Pruning Group 8, where pruning is generally limited to light shaping after flowering.
Correct plant identification is therefore essential before carrying out substantial pruning.
Frequently Asked Questions
What does light pruning mean?
Light pruning means selectively removing dead, damaged, diseased, crossing, congested or badly positioned branches without substantially reducing the entire plant.
Can I prune a Japanese maple in winter?
Japanese maples can bleed sap when pruned during late winter or early spring. Necessary pruning is generally better undertaken when the tree is in full leaf or during late summer.
Should I prune a newly planted tree?
Normally, only damaged, dead or structurally unsuitable branches should be removed during establishment. Unnecessary pruning should be avoided while the root system develops.
Can Group 1 plants be reduced in size?
Some can tolerate selective reduction, but repeatedly cutting back a plant that is too large for its position is rarely a satisfactory long-term solution. Species-specific advice should be obtained before substantial reduction.
Do pruning cuts need sealing?
Modern general practice is to leave correctly made pruning cuts uncovered. Wound paints and sealants are not normally required unless specialist advice indicates otherwise.
The Simple Rule for RHS Pruning Group 1
The easiest way to remember Group 1 is:
Prune lightly, preserve the natural shape and intervene only when necessary.
Explore more practical plant-care advice from Landscaping Emporium or browse our range of specimen trees.