The catalpa (Catalpa speciosa) is not native to Iowa. It was introduced as an ornamental tree because of its large, showy flowers. After the flowers bloom, long, cylindrical pods filled with small winged seeds form. This distinctive fruit hangs on the trees all winter.

catalpa tree in winter with no leaves
Catalpa Tree - Photo by Paul Wray, Iowa State University

Hardiness: Zones 4 through 9

Growth Rate: Medium to Fast. 15' over 7 to 8 year period.

Mature Shape: Tree with narrow, open, irregular, oval crown.

Height: 40-60 feet 

Width: 20-40 feet

Site Requirements: Very tolerant of different soil conditions. Prefers deep, moist, fertile soil, but can withstand extremely hot, dry environments.

Leaves: Opposite (whorled) simple

Flowering Dates: May - June

Seed Dispersal Dates: Late Winter - Spring

Seed Bearing Age: 20 years

Seed Bearing Frequency: Every 2-3 years

Seed Stratification: Seeds disperse in the spring and immediately germinate. No stratification period is needed.

The leaves are 8 to 12 inches long and heart-shaped. Leaves are thick and firm, dark green above and downy beneath. The fruit is a slender, 8 to 20 inch long pod that ripens in early autumn. The pod hangs on the tree all winter and opens in the spring before falling off.

grouping of white catalpa flowers and close up of single flower showing dark central stripes and yellow orange central spots
Catalpa Flowers - Photo by Paul Wray, Iowa State University

Catalpas grow rapidly. The trunks are short, often crooked, supporting a broad, rounded crown of slender, spreading branches and thick twigs.  The bark is thick, reddish brown, with scaly, longitudinal ridges.

Insects that Can Affect Catalpa



catalpa twig
Catalpa Twig - Photo by Paul Wray, Iowa State University

catalpa fruit look like long dark pods
Catalpa Fruit - Photo by Paul Wray, Iowa State University

catalpa leaves
Catalpa Leaves - Photo by Paul Wray, Iowa State University