Royal empress trees (Paulownia spp.) grow fast and produce large clusters of lavender flowers in springtime. This native of China can shoot up to 50 feet (15 m.) tall and wide. You need to start pruning royal empress trees early to help them develop a strong branch structure. If you want to know how to prune a paulownia and when to prune royal paulownia, read on.
Pruning an Empress Tree
The royal empress tree is dramatic and impressive, with large, heart-shaped leaves and lavender flowers. Since blossoms appear before the leaves open, they are especially showy and impressive. The royal empress tree grows extremely fast, up to 15 feet (4.6 m.) per year. One result of that speedy development is weak wood that is vulnerable to breakage.
Poor collar formation can also make branches vulnerable to break off at the branch crotch. Proper royal paulownia empress pruning takes care of these problems.
How and When to Prune Royal Paulownia
The question of when to prune royal paulownia is closely related to the issue of how to prune a paulownia. The when and how both depend upon the result you want to achieve.
One option is to prune the tree into a shorter garden-size plant. If you want to prune a paulownia like this, cut the tree back to about 4 feet (1.2 m.), leaving a few branches on this main trunk. Do this in the autumn. This type of pruning slows the rapid growth of the tree. Come spring, your tree’s branches will be filled with its trademark, heart-shaped leaves. The gorgeous blue flowers will also appear, filling the garden with a honeysuckle fragrance.
If you want to expand those beautiful leaves to a yard (1 m.) across, cut it back very hard in the winter. Pruning an empress tree severely like this in winter causes new leaves to open every spring. The very short trunk puts out green branches with enormous heart-shaped leaves.
If your intention in royal paulownia empress pruning is simply to strengthen the flowering tree, cut back dead wood in early spring. Don’t think of pruning royal empress severely at this time since you will eliminate the flowers.
After flowering, you can start pruning an empress tree more severely. Take out damaged and overlapping branches. Remove branches with poor collar attachment. Remove lower branches to allow passage below the tree.
If the tree appears spindly or crooked, cut it back to the ground and allow it to regrow. When it does, prune back all except the strongest shoot. It will grow in straight and strong.