Laburnum trees have green-tinged bark and vibrant three-pronged leaves. The trees have an erect form and reach heights of up to 10 metres. In spring, they produce long, drooping yellow blooms, which are followed by 30 cm long seedpods. Trim a laburnum tree to a single trunk form or allow it to develop multiple trunks for a shrub-like planting. Prune in summer, after all blooms have faded.
Choose the best tools for pruning laburnum trees. Hand shears and lopping shears are ideal for branches 0.5 cm to 2 cm around. Pruning saws are necessary for larger branches. Always use tools with extremely sharp blades and avoid ripping the bark when trimming.
Trim off dead, damaged and unattractive growth during any season.
Remove all suckers -- offshoots that develop from the roots -- from around the bottom of the trunk if growing in tree form. Leave the suckers in place for a thicker, shrub-like appearance.
Eliminate weak and fragile branches to encourage a flush of full and healthy foliage.
Trim rubbing or crossing branches back to the trunk or the larger branch that they extend from. Do not remove the growth flush with the trunk or main branch; make the cuts 1.5 cm to 5 cm above.
Cut the lowest branches level with the ground to create a tree form.
Prune the tree to control its size and shape by heading back, which means cutting some length from the branches. This should be done in a uniform fashion so the tree doesn't appear uneven. Sever the growth approximately 0.75 cm above a joining side branch or bud.
Pole pruners may be required to trim the top of mature laburnum trees.
Wipe over pruning tools with surgical spirit before and after pruning to avoid spreading disease between plants.
Each part of the laburnum tree is extremely toxic if consumed.