Hi everyone - could someone provide some guidance on this conifer please? It's a large hedge at the bottom of a garden I work in, and I think it's either the famous leylandii or chamaecyparis..?
Whatever it is, it's overgrown and trying to reduce the width and height but still keep it looking relatively ok is pretty impossble..
You do not have Lawson cypress, Cupressus lawsoniana. That has a translucent gland in the middle of each scale-leaf up the middle of the twig (I can't see any in your photos, but you'd should check the real thing). You need to hold a sprig up to the light to see it; otherwise each gland actually looks darker that the adjacent part of its scale-leaf (you can see that if you look closely at the circular photo here - http://www.keele.ac.uk/arboretum/trees/species/lawsonscypress/).
x Cupressocyparis leylandii, Leyland cypress, does not have that translucent gland
1. I cannot be sure that you have Leyland cypress, but I am sure it is not Lawson cypress.
2. There are many cultivars of Leyland cypress, as listed here (http://www.leylandii.com/types-of-leylandii.html), and the foliage differs between them to some extent.
3. There are other hybrid cypresses, derived from other species.
4. The hybrids share some characters with their parent species.
5. Because of 2, 3 & 4, it is difficult to ID Leyland cypress reliably, at least not just from foliage.
6. Some sources/people would have you believe Layland cypress is sterile, leading to the impression that it does not produce cones. That is false: cones are known, and in some cultivars they are not uncommon - eg. 'Leighton Green' and 'Rostrevor' bear cones readily when young (see http://www.leylandii.com/types-of-leylandii.html).
It is nigh-on impossible to cut back hard into an overgrown conifer hedge without it looking awful immediately afterwards. Some conifers will shoot from old wood, allowing a hedge to recover a decent appearance in a few years (eg. Thuja plicata, and Taxus baccata). Bit for other types, including Leyland cypress and Lawson cypress, I would always ask owners (before the hard-pruning is finished) if they really want it 'like that', suggesting the alternative of a fence (which takes up a lot less space in a garden, but which might be an issue in terms of local planning regulations). Another alternative is to use the conifer skeletons as a framework to train an evergreen climber over.
...Just my opinion.