Catalpas are best pruned just after blooming, and rarely need more than removal of the seed pods and attention to the structure of the tree: removal of crossing branches, and maybe some brushing out.

I love that thought. "What are you up to today?" "Oh, not much, just 'brushing out' my catalpa" Phil J

Nothing more fun than brushing out my citrus. I keep trying to make a party out of it, but my neighbors just walk slowly away, shaking their heads. Some funny circling of their ears with their forefingers, too! ; D

Actually, "brushing out" just means taking out all that dead or half-dead twiggy stuff that builds up inside the canopy.