16 October 2007
Gardens need shelter from winds and may need screening for privacy - a hedge provides excellent natural shelter.
Fences are quick to erect and provide an instant boundary, but deflect the wind, causing it to come down in a swirl on the leeward side where it can damage plants.
Hedges allow the wind to pass through, but slow it down. For every foot of hedge height, there are ten horizontal feet of shelter. Plants on exposed sites suffer more from wind than cold, but the shelter created by a hedge will protect tender plants.
We recommend that cutting hedges and trees is avoided between March and August as this is the main breeding season for nesting birds.
A hedge is a permanent feature so choose the location, eventual height and species composition carefully.
The best hedges contain several species that come into leaf, flower and fruit at different times, enhancing their wildlife value. A mixed hedgerow of native species is particularly appropriate for rural gardens where it will blend in with the surrounding countryside.
You can also plant a native hedge in urban areas, especially at the end of a garden to form a thorny intruder-proof barrier. Unless you keep its growth in check, it could develop into a tall impenetrable thicket though.
The eventual height of the hedge is important in the choice of plants. For example, rosemary and lavender are only suited to hedges up to 60cm (2ft) high, but hawthorn and beech can be maintained at 1-3m (3-10ft), or grown taller.
Leyland cypress has been planted widely over the last 20-30 years as instant hedging. Since it grows 1m (3ft) per year and can reach 45m (150ft), management problems outweigh advantages. A medium-sized specimen will drain the moisture and nutrients from a 3 metre (10ft) radius. Its wildlife value is minimal, other than as shelter, and most other plants are more beneficial.
Small trees, such as rowan and crab apple, are useful in a hedge. You can include them in a new hedge, or encourage a hawthorn or blackthorn to develop into a small tree in an established hedge.