Catalpa is a medium-sized shade tree with an open, irregular branching habit and heart-shaped leaves. It’s well known for its long, cigar-shaped fruits which often persist into winter. This native tree is one of few insect-pollinated species, providing showy clusters of white, fragrant flowers with distinctive nectar guides. Catalpa has unique nectar-producing structures on its leaves, called extrafloral nectaries. They can provide an additional nectar source to attract insect life, often attracting predatory insects, such as ants or parasitoid wasps which feed on the easily accessible nectar while also potentially providing some protection from insect pests.
Pollinator Type
Bees, wasps, butterflies, flies
Plant Type
Deciduous tree
Zone
4 to 8
Height
60-75 ft.
Spread
20-40 ft
Light
Partial Shade, Full Sun
Moisture Requirement
Dry Soil, Medium Soil, Wet Soil
Bloom Color
White
Bloom Time
May, June
Design Considerations
Catalpa matures into a large shade tree and does best in full sun, so be sure to provide adequate space for this large specimen. Seed pod production peaks every 2-3 years, creating a need for cleanup in manicured landscapes. Twigs tend to be brittle and easily broken, which can also contribute to cleanup needs. This tree’s irregular growth habit creates an interesting canopy form but may not be appreciated if a more uniform canopy structure is desired.
Care and Maintenance
Catalpa is a tough and adaptable plant that handles a range of soil/site conditions, although it prefers deep, moist and fertile soils. Tolerates alkaline soils well. Given the brittle nature of twigs and smaller limbs, the tree is prone to wind and ice storm damage and not suitable for close planting in areas with significant targets beneath the mature canopy.
Pest and Diseases
Relatively few, although leaves can be susceptible to powdery mildew. The plant is susceptible to verticillium wilt, do not plant in soils with confirmed verticillium. Larvae of our native catalpa sphinx moth may do considerable damage to foliage in years with high population size but no long-term impact to tree health should be expected and no control is recommended.
Establishment and Propagation
Easily grown from seed, no pre-treatment needed for germination. Typically planted from bare-root or container-grown seedlings given their wide availability commercially.
Commercial Availability
Commonly available.
Alternative Plant Selections
NA
Native Status
Illinois native statewide.
Fall Color
Insignificant; yellow
Growth habit
Catalpa forms an oval-shape when mature.
Number of Caterpillars that Use this as a Host Plant
