Catalpa (Catalpa bignonioides)
Discover the massive, fragrant blooms of Catalpa bignonioides, a medium-sized deciduous tree perfect for deep shade and moist soils.
Complete Plant Information
Overview
The Catalpa tree, scientifically known as Catalpa bignonioides, is immediately recognizable for its dramatic, showy flower clusters that appear in late spring. Native to the Southeastern United States, this deciduous tree brings a tropical feel to the landscape despite the distinctive, large heart-shaped leaves that can reach up to 10 inches long. While impressive during bloom, the foliage of Catalpa bignonioides may sometimes look coarse later in the season.
This species offers significant value as a large specimen tree, lending excellent shade to broad areas. It thrives best where it receives ample moisture, making it a robust choice for challenging locations. Gardeners seeking a bold architectural statement often turn to the Catalpa for its rapid growth and unique terminal displays.
Despite some perceived minor drawbacks regarding branch brittleness and late-season leaf integrity, Catalpa bignonioides remains a historically significant landscape element, particularly valued for planting in larger yards or areas needing substantial coverage. Its resilience in varied soil conditions adds to its practical appeal.
Fast Facts
- Plant Family: Bignoniaceae
- Plant Type: Tree
- Native Range: Southeastern United States
- Hardiness Zones: USDA Zones 5-9
- Size at Maturity:
- Height: 30-60 ft
- Spread: 20-40 ft
- Bloom Time: May to June
- Bloom Description: White with purple and yellow markings
- Sun Exposure: Full sun to part shade
- Water Needs: Medium to wet
- Maintenance Level: Medium
How to Grow
Planting the Catalpa tree is best done in spring or fall when conditions are moderate. Select a location that allows for its significant mature spread of 20 to 40 feet. Catalpa bignonioides is remarkably adaptable but excels in average, medium to wet, well-drained soils, and prefers moist, fertile loams. It demonstrates notable tolerance for seasonal flooding, drought once established, and poor soils.
Once established, the watering requirements are moderate, though it appreciates consistent moisture, especially during dry spells. Fertilizing is rarely necessary unless the soil is severely depleted; focus instead on proper site selection. Pruning should be done strategically to remove crossing or weak limbs to mitigate future breakage, though mature Catalpa trees sometimes naturally exhibit irregular forms.
As the season progresses, be aware that the large leaves are susceptible to cosmetic damage from wind, hail, and insects. No heavy winter preparation is usually needed in its native zones (5-9), but inspecting for weak wood or insect activity in late winter can prepare the tree for vigorous spring growth and bloom.
Landscape Uses
The towering stature and broad canopy of the Catalpa make it an excellent candidate for a dedicated Shade Tree, casting deep cooling shadows on broad lawns or over patio areas. Its unique aesthetic, highlighted by the spectacular spring floral display, ensures it captures attention. For a specific functional use, this tree is well-suited for Rain Garden designs due to its tolerance for medium to wet soil conditions and seasonal flooding.
While historically used as street trees, its potential for dropped debris (seed pods and leaves) means it works best where aesthetics and functionality outweigh neatness concerns. Consider placing Catalpa bignonioides away from high-traffic pedestrian paths or manicured borders where its coarse foliage might look out of place later in the summer. It thrives in large, naturalized settings or as a specimen where its scale can be fully appreciated.
Standout Features
Flower Qualities
- Showy
Fruit Qualities
- Showy
Noteworthy Characteristics
Catalpa bignonioides, commonly called Southern catalpa, is a medium-sized, deciduous tree that typically grows to 30-40’ (less frequently to 60’) tall with an irregular, broad-rounded crown. Very broad leaves emit a somewhat disagreeable aroma when bruised, contrasting with the fragrant, bell-shaped white flowers marked with purple and yellow that bloom prolifically. After flowering, seeds are held in long, narrow, dark brown seed pods often referred to as “cigar trees.”
Tolerances
- Deer
- Drought
- Black Walnut
Potential Problems
The Catalpa generally avoids crippling insect or disease issues, but it is susceptible to a few common problems. Watch for fungal issues like leaf spots, mildew, dieback, anthracnose, and twig blight. Verticillium wilt is also a noted threat. A highly visible pest is the larvae of the catalpa sphinx moth, whose caterpillars can consume leaves rapidly. Management often involves regular inspection; treating fungal issues proactively with fungicides or removing heavily infested foliage can help maintain the health of your Catalpa tree.
Frequently Asked Questions
What hardiness zones is Catalpa suitable for?
The Catalpa thrives in USDA hardiness zones 5 through 9. Ensure your planting location falls within this range for best results.
How large does Catalpa grow?
This hardy tree typically reaches heights between 30 and 60 feet, with a spread ranging from 20 to 40 feet, establishing a considerable presence in the landscape.
What sun exposure does Catalpa need?
Catalpa bignonioides performs best when situated in a spot receiving full sun to light part shade.
When does Catalpa bloom?
The dramatic flowering period for the Catalpa occurs between May and June, simultaneously displaying its attractive white blooms marked with purple and yellow interior patterns.
Conclusion
The Catalpa tree offers substantial aesthetic impact through its large stature and spectacular, fragrant spring flowers, making Catalpa bignonioides a powerful choice for creating bold architectural statements in the landscape. Its tolerance for wet conditions and poor soils adds significant practical value where other trees might fail. Before planting, confirm that your site is large enough to accommodate its mature size and plan for its presence in rain gardens or large shade applications.
Companion Planting
When planting near the Catalpa, focus on materials that either complement its large scale or contrast nicely with its massive leaves. Consider using lower-growing, moisture-loving shrubs like various Hydrangeas or wetland irises around the base, especially if establishing the tree near a rain garden feature. Avoid planting delicate, high-maintenance specimens near the Catalpa due to its potential for leaf damage and debris drop.
Wildlife Benefits
While the foliage can be a food source for the catalpa sphinx moth larvae, the tree offers other benefits. The nectar-rich, showy flowers attract various pollinators, including bees, during the May and June bloom time. Furthermore, the presence of the long seed pods may provide cover or foraging opportunities for certain bird species throughout the winter months, adding interest to the garden even when the tree is dormant.
