How to prune Catalpa
The deciduous Golden Indian Bean Tree (Catalpa) has large, exotic leaves, upright panicles of bell-shaped flowers in late summer, followed by slender, ornamental seed pods in autumn. Left to grow, it can reach heights of 12m, but when regularly pollarded, makes a fantastic large shrub at the back of a border. Here's how to prune your catalpa.
How and when to prune a catalpa
White flowers of 'Purpurea' look striking against its purple-black leaves
Image: Catalpa x erubescens 'Purpurea' from Thompson & Morgan
For regular catalpa trees, prune between late autumn and late winter when they're dormant. They respond well to hard pruning so don't be afraid to take out larger branches if needed. Remember to always make a cut just above a bud and at an angle facing away from the bud.
How and when to pollard a catalpa
If you want to pollard your catalpa, you're in luck – it's one of just a few trees that respond well to this treatment. Not only does it restrict the height to that of a large shrub, it encourages the catalpa to produce larger and more striking leaves.
- Pollarding is best done from late January to March.
- Grow your young tree to the height required - usually about 90-150cm.
- From one main trunk, choose 3-5 of the strongest and best placed branches to form the ‘scaffold'. This is the framework back to which the tree will be trimmed each year.
- With a pruning saw, cut the stems back hard to within 10cm of the stem, just above a pair of buds.
- Neat cuts will heal more quickly and prevent disease.
- Apply fertiliser and mulch.
- Continue the same process every one to three years as required, always pruning slightly above previous pollarding cuts to avoid going back into old wood.
- Thin out overcrowded new growth as the tree matures and remove new shoots to create an even balance.
- Remove shoots from the main trunk and keep the centre of the tree open to allow light and air to circulate.