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.
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.
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