Quoted from the conservation volunteers booklet:
Planning a Wildlife Hedge
Before planting, consider the purpose of the hedge. If the hedge is intended to be stock-proof( or to keep in pets), it needs to comprise at least 75% thorny plants. Hawthorn,with the addition of blackthorn or holly, often provides the mainstay of stock-proof hedges. Plants which provide berries or seeds for birds are desirable.
Planting hedgerow trees, such as oak or ash will attract more wildlife and, if allowed to grow, will provide shelter and shade.
Considerations:
Small plants (40-60cm tall) are cheaper, have a higher survival rate and often grow more quickly than larger ones.
We recommend planting a double hedge. Plant a formation that staggers the plants in opposite rows so that as growth occurs, gaps will be filled. A distance of 25-30cm is recommended between plants and between rows.
Numbers of plants needed
To estimate the number needed, measure the length to be planted and allow the following:
100 Metre Double Row Stockproof Hedge Using 8 Plants Per Metre - 800 trees:
600 hawthorn
10 holly
50 mixed trees (ash, oak, crab apple, rowan, etc.)
100 blackthorn
40 hazel
This is a typical mix, but other native species can be substituted. To keep the cost down and to produce an effective hedge, the 600 hawthorn (or even more) should always be planted.
Planting Tips
Make sure plants are well watered before applying a 2 inch layer of mulch to suppress weeds.
Where possible, trim plants by approximately one third immediately after planting to encourage bushy growth.
The plants will respond according to the preparation made at the time of planting, and also to the watering, feeding and weeding carried out in the first few years.