Wednesday, December 12, 2007

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!


Karen Hall said...

Thanks for a very useful post - I have inherited some very mauled looking hazels in this garden - you have reminded me that all is not lost!

The Constant Gardener said...

no problem - glad to be of help! Hazels are the easiest of trees to get back into shape again so I'm sure yours will look fabulous soon!

Miranda Bell said...

Hope you've had a good Christmas - love the article - am just about to embark on a lot of this type of work both here and for clients too - there are plenty of Hazels here in our woodland! The thing that a lot of people make a mistake with is pruning a hazel or similar to about a couple of meters in height each year and then end up with a thick mass of stems half way up! Much better to chop to the base or as you suggest thin out by removing the thickest stems.

Have a good New Year... Miranda

The Constant Gardener said...

Hi Miranda, happy Christmas to you too and I hope you have a great 2008!

You're so right about pruning hazels to shoulder-height... it looks so awful. Another one, I find, is to plant eucalyptus and then just let them head skywards. They look so skinny and pathetic like that... whereas with a bit of hard pruning they'll form a nice shapely tree or shrub with lots of stems.

Anyway, happy gardening!

John said...

I had several trees, dogwood and poplar, coppiced by pesky beavers. About 1" in diameter. I want full sized trees. Can I expect that from these stumps or should I start over?

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