Whether it’s an ornamental flowering border or a conifer screen, all hedges need cutting or trimming each year to help maintain their health and shape.
Hand shears are fine for smaller hedges – make sure they are kept sharp though. Blunt shears will bruise the plant stems and make the job a lot harder, as well as leaving you with an unhealthy, browning hedge.
If you have a large hedge or a few hedges its worth investing in an automatic trimmer – choose electric, battery or petrol depending on your situation. If opting for a cordless trimmer, buy one with a spare battery as there's nothing worse tahn waiting for the used one to charge up! Always use a safety socket with RCD if you have an electric trimmer, and be sure to wear protective clothing, gloves and goggles. Buy the best safety gloves you can afford, your fingers will thank you!
Whatever tool you use and whatever type your hedge, it is a good idea to lay a tarpaulin or sturdy dustsheet underneath the hedge before you start. That way you can easily catch all the clippings and put them into a bin or bag for disposal.
When to Cut
The time of year for cutting depends on the variety and age of the hedge. When a new hedge is planted and for the first couple of years of its life, a hedge requires formative pruning – for deciduous species such as hawthorne, beech, forsythia and fuschia, this should be carried out in the winter. For evergreens such as box, holly, privet, cypress and yew, formative pruning should be carried out in the spring.
Maintenance pruning is a different matter, and depends on whether it is a formal or informal hedge, and of course the plant varieties used. Below is a rough guide to when different types of plant should be pruned:
- Buxus sempervirens box), Ligustrum (privett), Lonicera nitida and Cuprocyparis leylandii (Leyland Cypress) will all need pruning two or three times during the growing season
- Prunus laurocerasus (laurel) should be pruned twice in the growing season
- Ilex aquifolium (holly) needs pruning just once in late summer
- Chamaecyparis lawsoniana (Lawson cypress) should be pruned twice – in spring and summer
- Taxus baccata (yew) and Crataegus monogyna (hawthorn) both require pruning twice, in summer and autumn
- Thuja plicata (western red cedar) needs to be pruned in spring and again in early autumn
- Carpinus betulus (hornbeam) and Fagus sylvatica (beech) should be pruned once, in late summer
- Berberis, Escallonia, Lavandula (lavender) and Forsythia should all be pruned immediately after flowering
- Pyracantha should be pruned in late summer
- Fuchsia and Rosa rugosa (hedge rose) both need pruning in spring.
Cutting Formal Hedges
Use a string line secured with canes to give you a cutting guide, ensuring that you cut in a straight and level line. Provided the hedge is not too bushy and you can reach comfortably over it, cut along the top first. If it is a tall hedge and you are using a ladder or platform, be very careful to ensure it is set in a sturdy position, and get a friend to hold you steady. Do not over-reach as this can be very dangerous. Make sure you keep the shears horizontal for a flat top, and ensure you remove all trimmed foliage from the top of the hedge.
When cutting the sides, start from the bottom and work up in a sweeping motion – this allows the cut branches and foliage to fall away. If you started from the top, the foliage would get stuck in the lower branches and make your job much harder.
Make sure that the sides are slightly tapered so that the base is wider than the top. This allows sunlight to reach the bottom of the hedge and encourages growth.
Some plants respond better to a hard pruning than others. When cutting conifers be careful not to cut into bare wood as you will end up with a hole in your hedge. Do not cut back further than half an inch from the last green shoot.
Privett and beech are both hardy and resilient to a hard pruning.
Cutting Informal Hedges
Trimming an informal hedge is much the same and pruning a shrub – they shouldn’t need much hard pruning as an informal hedge is allowed to grow naturally so that its shape isn’t spoiled. Shears are not usually suitable for pruning an informal hedge – you will get on much better with secateurs, and loppers if needed. To keep an informal hedge in good shape you will occasionally need to remove old stems or cut branches to keep the hedge within its boundary.