Siberian elms are a fast growing tree that can reach a height of 75 feet. Because they are weak wooded, it is best to start shaping the tree by pruning, when the tree is quite young. Siberian elms can also be pruned into a hedge. Since Siberian elms are deciduous, it is best to wait until early spring to start pruning your tree. Siberian elms can reach a height that will make it difficult for the home gardener to prune the tree by themselves. Large trees may require a professional tree trimmer to be hired to properly prune it into shape.
Sharpen your pruning shears before starting to prune your Siberian elm. Working with sharp shears will cause less damage to the tree, making it less prone to pick up any diseases.
Spray your pruning shears with a solution of 50 percent bleach and water after every cut. This will cut down on the chance of transporting Dutch elm disease from one branch to the other as you prune them. Siberian elms can be carriers of this disease.
Cut branches on young Siberian elm trees that are creating narrow crotches. Cut away any branches to open the crotch area up, making it wider. Older Siberian elms are known to split in a narrowed crotch area when filled with ice and snow. Widening the area will eliminate this problem.
Prune any dead or injured branches that are dying, regularly. This will not only keep the tree in shape, but it will help prevent problems in the future for the tree's growth and health.
Cut off only the first one-third of any branch, when pruning the tree to shape it up. Make your cut right about a leaf eye. Cutting off any more of the branch will stress the tree and possible stunt its growth.
Prune any branches that are crossing over each other or rubbing against another one. Trim back any branches that are growing over roofs, or interfering with structures or power lines as soon as you notice they are a problem.
Trim all the main branches back by one-third, if you desire the Siberian elm to be denser. Several new branches will sprout from where you made your cut and the tree will grow back thicker.
Trim branches from the center of the tree, if the Siberian elm is too dense and not opened up enough. Cut every other branch to thin the midsection and to avoid having the tree look completely bare in the center.
Trim the entire Siberian elm to keep its size and shape under control, if growing a hedge. Pruning can be done throughout the entire growing season.