The Dwarf Catalpa—or “Globe Trumpet Tree”—gets its name from its naturally rounded canopy. The cool thing about this specific variety is that you don’t actually have to prune it into a ball shape; unlike many other ornamental trees, it grows that way all on its own!
Pruning Young Trees
Since the tree is a natural overachiever when it comes to its shape, formal “topiary” pruning isn’t usually necessary unless you’re going for a super-manicured look. However, if you want a canopy that’s thick and lush, it helps to give young trees a little extra attention during their first few years. Instead of just trimming the tips, give them a bold, heavy cut. This encourages the tree to push out more branches, resulting in a much denser and more compact crown down the road.
Thinning Out the Canopy
Once your tree is established, you can put away the heavy-duty saws. In later years, all it really needs is a bit of thinning out every now and then. Focus on removing any dead or diseased branches. When you do this, make sure to cut the branch off completely; if you leave stubs, the tree tends to sprout “witch’s brooms” (clumps of weak, twiggy growth) from the cut site.
Skip the Fall Pruning
Unlike many other garden favorites, you should never prune a Globe Trumpet Tree in the fall. These trees are originally native to the southern United States, so they aren’t naturally built for freezing temperatures. Making fresh cuts right before winter weakens the tree and makes it way more vulnerable to frost damage. Instead, wait until spring to thin out the branches. This gives the tree the whole summer to recover and grow new wood. Since these trees don’t start leafing out until May, there’s no rush to get out there in March—you can easily tackle this task a bit later in the spring.
To keep your Globe Trumpet Tree looking its best, just remember:
- No formal shaping is required.
- Always remove dead or diseased wood.
- Stick to pruning in the spring.
