How and When To Prune Hawthorn Hedges
The breeding season for most nesting birds is between March and August so it is therefore recommended not to clip hedges during that time to avoid disturbing nesting birds. In fact, it is a criminal offence in the UK to damage or destroy the nest of any wild bird while it is in use or being built. However, different types of hedging may need clipping at different times of year to achieve the best results, so how do you achieve the best balance?
To maximise the next crop of flowers, most flowering hedges are best cut straight after flowering each year, if possible, but to do so would inevitably reduce the number of berries, fruit, seeds or nuts in autumn - not ideal for varieties chosen for ornamental berries such as Pyracantha, as well as reducing food sources for wildlife. Most deciduous hedges could almost be clipped at any time of year, avoiding frozen conditions of course. Evergreen hedges usually respond best if cut during the growing season in spring or summer, in fact they can suffer damage if clipped in the autumn.
There’s no ideal time to satisfy every possible criteria for pruning hedges, but February is the month which can often come closest. Deciduous species can be pruned in mild weather now and, although it’s too early to give evergreens a full hedge trim with shears or hedge clippers, when a winter is as mild as this one has been it wouldn’t do any harm to give a light trim (or selective restorative/formative pruning for that matter) to tidy up any wayward shoots on broad-leaved evergreens in mild weather.
As well as avoiding the nesting season, another benefit of pruning in February is that there won’t be any “wasted” growth, by that I mean that the hedge plants won’t yet have put on any extension growth only for it to be cut off later; pruning now will induce side shooting and thickening of the hedge from buds further back, within the canopy, giving a thicker and more dense hedge.
Around the British countryside the most widely used hedging plant is of course Hawthorn, Crataegus monogyna; it’s tough, grows well in a very wide range of conditions, is early into leaf and, with regular pruning, forms a dense hedge. Unlike many more ornamental options, you don’t have to be too fussy about how you prune Hawthorn - it is common for farmers to use tractor-mounted flail cutters to trim Hawthorn field hedges, something which you’d never dream of doing with a formal hedge! However, to keep the hedge dense all the way down to the base it is important to prune it with slightly sloping sides, wider at the base than at the top, allowing light to reach the foliage all the way down.
If not clipped as a hedge, Hawthorn will eventually grow into an attractive small tree. However, since it doesn’t naturally grow very straight on its own it doesn’t tend to be grown very often as a tree commercially, but there are other members of the Crataegus genus which are more tree-like in habit and will make excellent garden trees. “Paul’s Scarlet” is a popular choice, with semi-double or double deep-pink flowers; unfortunately, it doesn’t produce many berries as the fully double flowers are sterile.
A less commonly seen member of the Hawthorn family is Crataegus prunifolia, which has a leaf more similar in shape to that of a cherry tree than a Hawthorn, and glossier too, but this is a small tree which really earns its place in the garden. It carries hard thorns which are over an inch long, making it an ideal boundary tree for security planting… and Crataegus prunifolia can also be planted in a shrub form to be clipped into an impenetrable security hedge. The bark colour of the twigs and thorns starts as a deep plum-colour, maturing to a silvery-grey. The white flowers are very similar to our native May Blossom, although they are produced about three weeks later, but the greatest features of this stunner show themselves in autumn when the foliage turns first golden yellow, then fiery orange and, if exposed to enough direct sunlight in summer, bright scarlet and coppery-purple. Whilst this colour change is happening, the berries mature into large, deep-red Haws, clearly displayed against the golden yellow leaf tints to entice hungry birds.