Hedges – Common Tree Species and Maintenance

In this article, I will attempt to bring together information from the industry guidance (from BS3998:2010), as well as the latest thoughts from some of the leading authorities (RHS, Arb Association), as well as my own experience looking after hedges over the years. The aim being to provide a concise and easy to understand guide of how to look after a selection of common hedge plants through the seasons.

Cypress

Being the proud(!) owner of probably the biggest cypress hedge in Comrie, I understand first-hand the importance of an annual/regular maintenance plan. If you don’t keep on top of them, they will gradually (and somewhat irreversibly) larger and larger as the years go by. My example is in excess of 40 years old, and despite being well maintained throughout it’s life, is now nearly 5m thick in places!

Some species of cypress hedges (Lawson’s, Leyland) if left un-checked can grow in excess of 20m, and the tops can be very quick to race away if even just a season of trimming is missed. They are very fast growing.

The main thing to consider when looking after a cypress hedge, is that it is very prone to damage by frost. Frost damage manifests as unsightly brown “dieback” of the leaves. Because of this, coupled with the very late frosts we seem to get these days, I wouldn’t recommend any trimming before 1st May, or after 1st of October. There is of course an exception to this rule, which I’ll explain a bit later!

For annual maintenance of cypress hedges, I always recommend a trim in the spring, and a trim in the early Autumn. This should keep it in check nicely, and mitigate as much as possible the risk of damage by frost, as there should be plenty of time for the cuts to heal before the frost comes again.

 If you require you cypress hedge reducing in height, it is best to do this work during the winter, 1st December to 1st March. The reason for this is wildlife, and birds nesting. These conifers provide excellent cover for a whole range of species of songbird, so its very important we don’t disturb them during this time.

 Most cypress hedges will respond just fine if you remove no more than 30% of height at a time. Once topped, allow a full season at least before trimming again, to allow the tree to recover, and start establishing canopy again. You should now be able to maintain the height with annual trimming once recovered.

Yew

My favourite of all our evergreen native species for hedging, this tree is amazing to work with!

Yew is extremely hardy, and can be shaped over time into pretty much whatever shape you desire! It provides all the cover benefits the cypress does, but unlike cypress, yew can recover a nice new layer of canopy from being cut right back to bare wood.

There is no special time of year to trim a yew hedge in my opinion. It doesn’t seem to mind the frost so much, but it makes sense to have a spring/Autumn trimming plan if you are trying to keep a nice formal finish.

Again for harder reductions/cut backs, best leave until winter time.

Laurel

This popular evergreen broadleaf is excellent at providing cover, and likes our climate in central Scotland very much! I was involved in a site clearance last year where some of these plants had be left un-checked for 25 years. The size and scale of the trunks was extremely impressive (and extremely dangerous to dismantle).

These hedges respond really well to being cut back hard in the springtime, and if you wish a formal look to be maintained (like any topiary really), again in the late Autumn. Watch out for suckers popping up from the roots. These trees are invasive, I’m constantly keeping on top of suckers from my neighbours impressive specimen, these are very difficult to remove when established. Unlike Rhododendron, these are almost impossible to dig out by hand if they have spread by root, so a stump-grinder could be the only solution for their full removal.

Beech (fagus)

Showing off a nice deep green during the spring and summer, followed by a lovely golden brown throughout the autumn and winter, beech is my favourite tree for hedging.

I recommend working on Beech hedges during the late winter, early spring (before budding) so 1st Feb – 1stApril roughly. There is nothing wrong particularly with trimming them just after the leaves brown up, but then you lose that lovely golden cover, as the trimming process usually causes most of these brown leaves to drop, where they would normally hold on until budding time. It’s more of an aesthetic choice In the case of beech.

Prunus/Malus

Maintained in a pleached from, these trees can be trained to provide a hedge like form. These trees will obviously need a special care, so please don’t just whack them with a hedge trimmer! Apples are best pruned late winter, but trees in the prunus family are best left unto early to mid-summer, due to the risk of infection by “silverleaf”.

Catoneaster / Berberis

These guys are very popular in the Strathearn area for hedging, and they are super easy to trim and shape (although be careful with the thorny berberis). These are quite good at covering any gaps, and is quite commonly seen as part of a mixed hedge with Holly and other trees and shrubs. They are hardy and don’t mind to be cut back hard.

Again, Spring and Autumn trims would be suitable if you want to maintain a formal finish.

There are of course many other suitable hedging plants out there! Give us a call to discuss a maintenance plan that suits your hedge!