We don't have synonyms for catalpas yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are catalpa, Catalan and catalogs.
(n) :
Any tree of the genus Catalpa, in the family Bignoniaceae. The two North American species, the southern catalpa, Catalpa bignonioides, and the northern catalpa, Catalpa speciosa — along with the yellow catalpa, Catalpa ovata, from China — are often planted as ornamentals because of their showy flowers and decorative bean pods, though others regard the bean pods as a nuisance.
(n) :
Any tree of the genus Catalpa, in the family Bignoniaceae. The two North American species, the southern catalpa, Catalpa bignonioides, and the northern catalpa, Catalpa speciosa — along with the yellow catalpa, Catalpa ovata, from China — are often planted as ornamentals because of their showy flowers and decorative bean pods, though others regard the bean pods as a nuisance.