Catalpa Speciosa Tree

The Northern Catalpa speciosa is an interesting, mostly deciduous and beautiful tree. In some areas, the large leaves can remain green or turn dark brown and remain on the tree over winter.  It is sometimes called “the bean tree” because of its long string bean or cigar-like seed pods. 

Catalpa is a flowering tree species in the family Bignoniaceae.  

Some archeological investigations in West Virginia have discovered catalpa trees dating back to the 1500-1700 era.  It was thought that the tree was originally limited to the midwest region. A native tree in North America, its range is from the Rocky Mountains to Texas in the west,  to the entire east coast from Florida into eastern regions of Canada. The Southern Catalpa bignonioides is similar, with slightly smaller leaves. 

Catalpa are sometimes mistaken for the invasive Pawlonia tormentosa from China.  It is also sometimes mistaken for the Tung tree, Vernica fordii, both of which have similar large leaves. 

The Catalpa has been planted as a shade tree due to its very large (10-13 inch,) elongated, heart-shaped leaves. The leaves are opposite, or whorled, generally occurring in threes, with one of the leaves appearing smaller than the others.  It is a medium-sized tree, approximately 80 feet in height. It has crooked branches and an irregular shape. The seed pods and large leaves make it easily identifiable. 

White bell-shaped, sweet smelling blossoms with yellow and purple spots appear in late May. These blossoms can retain their sweet aroma for a long period. The bean-like seed pods contain small, flat seeds with two wings. They fall in late summer, or can remain on the tree over the winter. The wood is soft, dimensionally stable, and has been used for furniture and guitar sound boards. It can be beautifully figured.  

A symbiotic relationship exists with the Catalpa sphinx hawk moth, ceratomina catalpae, which feeds exclusively on the Catalpa leaves. The moth lays eggs on the underside of the leaves of the tree, and the dark green and sometimes black and yellow striped caterpillars hatch and feed on the leaves all summer long. These can sometimes completely defoliate the tree. The catalpa leaves can grow back quickly, and this can occur several times over the summer. Studies in Florida have determined that the defoliation rarely kills the tree.  This relationship apparently dates back thousands of years.  The caterpillars are highly prized as fish bait, especially in the south where Catalpa have been grown specifically to cultivate the caterpillar.  While it is not specifically known what the trees derive from this relationship, it is suspected that at least the caterpillar droppings fertilize the trees.

Article by FCFCDB

 Nature Note for 04/14/2023