There are also species of shrubs and herbs that are characteristic of old hedges or woodland, such as Spindle () along with a wide range of herbaceous species growing in and around the base.
This mix of species provides a source of nectar and pollen from early spring until well into winter, supporting a wide and varied range of insects.
The tree species used for the hedging may also relate to the history of the garden.
More detail on the regulations and their use is given in ‘Over the Garden Hedge’.
A single species hedge is likely to be less than 100 years old whilst a 1,000 year old hedge is likely to contain ten to twelve species. Hedges may have been planted with a mixture of species and there is geographical variation.
In upland areas and the north of England hedge species are less diverse.
Very old, over-mature hedges or overgrown hedges can be rejuvenated or restored.
The Royal Horticultural Society provides advice about planting, maintaining and renovating garden hedges.
Statutory regulations were introduced under the Anti-social Behaviour Act 2003 Part 8, to address the problem of neighbourly disputes over the height of boundary hedges.