Hedges are characterised by the fact that they are trimmed at intervals. Trimming encourages the hedge plants to produce bushy, branching growth which forms a dense barrier, and also keeps the hedge to the required height and width. Left untrimmed, most hedge shrubs will eventually grow into trees.
Frequent trimming tends to reduce the value of the hedge for wildlife, although well-managed, trimmed hedges can be both an effective barrier and a useful habitat, as well as being of landscape value.
Nearly all hedge trimming is done mechanically, using tractor-mounted flails. Notes are included on trimming by hand, which may be useful on small conservation sites and wildlife gardens. Pruning newly planted hedges is described here.