Native Plants

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Wednesday - May 23, 2007

From: Austin, TX
Region: Southwest
Topic: Trees
Title: Caterpillars on catalpa trees and hardiness of catalpas
Answered by: Damon Waitt

QUESTION:

A volunteer catalpa tree has recently popped up near the edge of our swimming pool. The foliage is lovely, so I'm considering allowing it to stay. This one has already proven to be a fast grower . . . but how do they do long term. Do they really get covered in worms all summer?

ANSWER:

There are two species of Catalpa in North America, Catalpa speciosa (northern catalpa) and Catalpa bignonioides (southern catalpa). Northern catalpa is a 75-100 ft., deciduous tree with a narrow, oval crown. Southern catalpa reaches 25-40 ft. in height with an equal or greater spread. Both species are fast growing and relatively short-lived. Either species may become weedy or invasive in some regions or habitats. Larva of the catalpa sphinx caterpillar (Ceratomia catalpae) eat the leaves and complete defoliation may occur in some years.

The biggest management problem with catalpa used as an ornamental is litter. They will drop a heavy load of flowers in the spring, then leaves in the fall and finally a lot of large seedpods in the winter. In other words, you will be spending a lot of time cleaning your pool.

For all these reasons, many people (Mr. Smarty Plants included) consider this nearly indestructible tree to be a bit of a nuisance despite its large showy flowers and tropical foliage.

Read this USDA Plant Fact Sheet to learn more about Catalpa.

Catalpa bignonioides

Catalpa speciosa