Ask Mr. Smarty Plants

The Chitalpa tree (X Chitalpa tashkentensis) is a hybrid from a cross between Catalpa bignonioides (Southern catalpa) and Chilopsis linearis (Desert willow).  The two plants are from the same family (Family Bignoniaceae, Trumpet-Creeper Family) but are not only different species, but also from different genera (Catalpa and Chilopsis).  Since the Chitalpa tree is a hybrid it is usually sterile and doesn't produce fruit.   That's one of the desirable features of it because it doesn't leave a "mess" under it from the falling seed pods.  You can read the description from Oregon State University. 

Now, I am a bit confused.  Do you actually have a Chitalpa tree and did it produce seeds and one of those seeds grew into the bush you are asking about?   If this is the case, it is very unusual since Chitalpa trees are sterile and don't produce fruit containing seeds.

Is it possible that your bush is actually a young Chilopsis linearis (Desert willow)?   Its maximum height is 12 to 40 feet. Here is a photo of the long, thin seed pods of Chilopsis linearis (Desert willow) and a photo of its trunk and bark from Oregon State University.  You can see photos of the seeds from the seed pods on the Vascular Plants of Gila Wilderness site.

Or, is your plant a young Catalpa bignonioides (Southern catalpa) tree?  Its maximum height is 25 to 40 feet.  You can see many photos of Catalpa bignoniodes, including its seeds and trunk, at the Discover Life site.

Since the Chitalpa tree is a hybrid and not technically a North American native, it doesn't appear in our database, but you can see photos and more information from Delange.org and Cuyamaca.net.  Perhaps by comparing photos of the three trees you can determine the identity of your bush.