Northern Catalpa Tree CATALPA SPECIOSA Hardiness Zone: 4 Prices by Size: 2 in. Cal., W.B. - $80.00 2 1/2 in. Cal., W.B. - $95.00 3 in. Cal., W.B. - $110.00 4 in. Cal., W.B. - $200.00 [Your browser doesn't support IFrames. Click here to find the USDA hardiness zone for your zipcode.]