Back to work

At last - the sun is shining, the frost has stopped (for the time being at least) and I can get outside again. I realised this morning that what with a combination of bad weather and Christmas, I only gardened one week in December... that must be some sort of record for me.

One thing I did do in my own garden - which didn't require treading on the frosted grass, which at one point didn't defrost for five days in a row - was to sort out my willow tree. This is the goat willow (Salix caprea) that's by my pond - you can see another picture of it covered rather fetchingly in snow here. You might be able to see from the earlier picture that it was overhanging the fence quite considerably - well on the other side of the fence happens to be my cut flower garden, so it was quite urgent that I take out the overhanging branches and let in a bit more light.

The depths of winter are a great time for pruning trees - you can really see what you're doing, and create a good, balanced outline. You can also get a good look at the general health of the branches, and those which are crossing other branches or generally growing in the wrong direction become very obvious when they're not hidden by leaves. In this case, I aimed for quite a tall, upright shape which was well-balanced but didn't cast too wide a shadow.

When pruning trees, you need to take care not to cut too close to the trunk. If you look at where a side branch leaves the main branch or trunk, you'll see there's an obvious junction. This is called the collar - it appears as a slight swelling between trunk and branch. You should cut on the branch side of the collar - not through it, or on the other side of it, as it contains lots of good hormones which promote the rapid healing of the wound. You can see where I've done this on the big cut facing you in the picture.

It's a good idea too to cut quite close to the collar, as if you leave too much of the branch on the tree, it'll die back and could rot and let in disease - I could have cut fractionally closer here, in fact, and it's not always easy to get it absolutely right. One tip is to cut away the branch little by little, from the far end back towards the trunk, so you get several chances to cut it to exactly the right point.

Keeping trees in check

I spent a happy hour or two with the chainsaw the other day, converting an ill-advised pollard into a coppice in a client's garden.

The difference between pollarding and coppicing is pretty straightforward, though people tend to get a bit confused in a "stalactites and stalagmites" sort of way. Pollarding is when you allow the tree to develop a single trunk, and then when it's got to the height you want, you cut the leader to that point and allow it to grow new shoots from there. It's good if you want to limit the height of a tree yet allow it to provide some screening too.

Another client has a row of pollarded lime trees growing right the way along the length of her garden: very elegant, and with a little judicious pruning of the inevitable wispy sideshoots that sprout from the trunk from time to time, it's easy to keep them good-looking all year round. Willow also makes a good pollard: a local willow producer grows pollarded willows all along the streams in the field behind his house and harvests the stems each winter for use in basket-weaving.

It doesn't work for all trees, though. The client I visited the other day had tried to pollard a hazel tree, which doesn't lend itself to the process well at all. Hazels sprout like crazy from all up the trunk and from the base as well as soon as you try to limit their growth, meaning you quickly get not an elegant column but more of a bizarre upright hedge effect. In this particular case, the client had allowed one or two of these shoots to develop and pollarded those too, so you ended up with a multi-stemmed pollard, complete with wild beardy clumps on the trunks, if you can imagine such a thing: not a pretty sight.

With hazels it's much better to exploit the naturally multi-stemmed habit and coppice them. This involves cutting the whole tree down to about 6" above ground, which looks drastic, but then next spring it produces a lovely spray of even, whippy shoots to the same height all round, giving a shapely shrub-like effect. You allow this to grow on for 2-3 years, and then do it all over again (and use the wonderful straight stems for beanpoles while you're at it). An alternative, if you don't fancy losing your hazel completely every 3 years, is to take out a third of the stems each year - choose the thickest or any which cross other stems or grow in the wrong direction. That way every three years you'll have rejuvenated the whole coppice anyway.

The coppicing technique can be used to keep otherwise wayward trees like eucalyptus in check (the young leaves it produces when treated this way are fabulous too). And if you coppice willow and dogwood, you'll make the most of the vibrant coloured stems they produce in winter. Pretty and practical, too!