Anne Swithinbank’s Masterclass

Anne Swithinbank’s masterclass on: taming large conifers

The best cuts leave conifers looking natural and healthy, as with this Picea glauca var. albertiana ‘Conica’

Right image and inset image: Alamy

Anne’s top tips

How to best control your conifers

The annual removal of taller stems from Thuja is easy for us to achieve safely and keeps our stand of conifers under control Large conifers like this Picea pungens ‘Hoopsii’ can tower over borders

How do I tame large conifers?

QWe have a stand of cypress-like conifers that we want to keep but they are too big. I’ve heard they don’t respond well to pruning, so how can we reduce size while enjoying privacy and their evergreen shape? Angela Clegg, Penrith, Cumbria

ALarge conifers suffer from bad press when they’ve been badly sited and neglected. They can tower over boundaries, shade out borders, block views and suck the ground dry in summer. However, wellmanaged, these fast-growing giants can be an asset in medium-to-large gardens. In ours, we maintain a small belt of existing conifers to screen nearby buildings and shelter the greenhouse from frost and northerly winds. Should you have an overgrown hedge or a group of Santolina chamaecyparissus , x Cupressocyparis leylandii or Thuja, then avoid cutting hard back into older wood because they don’t sprout back readily as would a yew. However, it is feasible to remove the tops from these conifers, to prevent them from rocketing up. Energy is pushed into lower growths, but these in turn will grow up and need thinning. The trick is to evaluate your conifers each year during autumn and winter when birds are not nesting. The aim is to tidy during mild spells by reducing some of the furthest-reaching growths. Carried out regularly, this work is usually within the scope of competent, well-equipped amateur gardeners. However, if trees have been neglected, or you have any doubts about safety, hire a tree surgeon to do the work for you. This is a two-handed job, and starts with a discussion about which long stems to remove. The aim is to leave behind a natural-looking stand of conifers that don’t look pruned, with no dead stems or foliage showing.

Conifer do’s and don’ts

DO remove larger branches in such a way that the cuts are covered by the tips of lower growths. If dead wood is accidentally exposed, do clip away dead foliage or try tying healthy branches together to disguise it. Don’t forget that once you begin pruning a large conifer, it will grow back with vigour and need regular attention.

Trim leylandii so cuts are covered by the tips of lower growths

1For sawing through thicker stems, we rely on an extending pole saw with hooks to help bring down the branches after cutting.

2Saw through the targeted stem, leaving only green healthy material behind. An assistant is useful here to catch the branches.

3Once the larger stems have been reduced, thin out those of a smaller diameter by using a pair of long-reach loppers.