Northern Catalpa vs. Southern Catalpa: Understanding the Catawba Tree
Dive deep into the distinguishing features, history, folklore, and ecological value of the Northern and Southern Catalpa trees.
The Catalpa tree, often called the ‘catawba tree’ or ‘Indian bean tree’, is rooted in North American landscapes and lore. Two distinct species claim prominence: the Northern Catalpa (Catalpa speciosa) and the Southern Catalpa (Catalpa bignonioides). Though often confused due to their similar appearance, these species possess unique characteristics, ecological roles, and cultural significance. This article explores the distinctions, history, and value of these remarkable native trees.
Table of Contents
- Botanical Overview
- Identification Guide: Northern vs. Southern Catalpa
- Habitat and Geographic Range
- Growing Conditions and Landscaping Use
- Folklore and Historic Uses
- Value to Wildlife and Ecology
- Frequently Asked Questions (FAQs)
Botanical Overview
The genus Catalpa belongs to the Bignoniaceae family and features two prominent North American species:
- Northern Catalpa (Catalpa speciosa)
- Southern Catalpa (Catalpa bignonioides)
The trees are deciduous, noted for their large heart-shaped leaves, showy white flowers, and long seed pods reminiscent of cigars or beans. Despite their similarities, their native ranges, appearance, and ecological roles set them apart.
Identification Guide: Northern vs. Southern Catalpa
| Feature | Northern Catalpa | Southern Catalpa |
|---|---|---|
| Scientific Name | Catalpa speciosa | Catalpa bignonioides |
| Height (Mature) | 40–60 feet (occasionally taller) | 25–40 feet |
| Spread | 20–40 feet | 20–35 feet |
| Leaves | Large, heart/oval-shaped, 8–12″ long, mostly odorless when crushed | Large, heart-shaped, slightly smaller, may have musky odor |
| Flowers | Larger, white, bell/trumpet-shaped, with fewer purple spots | Smaller, white, often with more orange or purple spots |
| Seed Pod | 15–22″ long; thicker; seeds have more fringed hairs, blunt ends | 8–15″ long; slender; seeds have fewer hairs, pointed at one end |
| Bark | Vertically furrowed; rougher appearance | Bark exfoliates in thin scales or flakes; smoother look |
| Growth Habit | Tall, upright trunk, larger leaves, narrower crown | Shorter, more squat, wider-spreading canopy |
| Flower Time | Late spring to early summer (May–June) | Late spring to mid-summer (June–July) |
| Native Range | Midwest and lower Midwest/Southeast US | Southeastern US to Florida and East Texas |
Key Identification Tips
- Flowers: Northern catalpa flowers are larger and coarser, while southern’s are a bit smaller with more pronounced orange or purple markings.
- Seed Pods: Northern catalpa seed pods are longer and thicker; southern catalpa pods are shorter and thinner.
- Seeds: Northern catalpa seeds have more pronounced fringes on both ends; southern’s are less hairy and pointed at one end.
- Bark: Look for rougher, vertically furrowed bark on the northern; southern’s bark comes off in thin, flat plates.
Habitat and Geographic Range
- Northern Catalpa is historically native to riverbanks and floodplains of the Midwest and lower Midwest (Illinois, Indiana, Missouri, Arkansas, Tennessee). Despite its name, it is actually more southern in original distribution than its reputation suggests.
- Southern Catalpa grows natively throughout the Southeastern United States—particularly in Alabama, Georgia, Florida, Louisiana, East Texas, and parts of Mississippi and South Carolina.
Both species have been widely planted beyond their original ranges, sometimes blurring the line between native and naturalized populations.
Growing Conditions and Landscaping Use
Catalpas are robust and adaptable, making them attractive for home landscapes, parks, and restoration projects.
- Soil Tolerance: Both species handle a broad range of soils (acidic, alkaline, rich, sandy, loamy, clay, wet, or dry), though southern catalpa thrives in rich, moist conditions.
- Sun Exposure: Both require at least four hours of direct sunlight and will not thrive in deep shade.
- USDA Hardiness Zones: Northern catalpa: 4–8. Southern catalpa: 5–9.
Both species may be grown from seed or rooted cuttings, and are often employed as shade trees, in restoration plantings, or in urban settings for their ornamental value.
Folklore and Historic Uses
Catalpas are woven into American lore and everyday use:
- Catawba Worms: Southern catalpa is notorious for hosting the catalpa sphinx moth caterpillar, known as the ‘catawba worm’. These caterpillars are prized bait for southern fishermen, especially for catching catfish. Generations of anglers sought out catalpa trees for the worms they provided.
- Lumber and Uses: Catalpa wood is lightweight, resistant to rot, and was historically used for fence posts, railroad ties, and cabinetry.
- ‘Cigar Tree’ Name: The nickname comes from their long, brown seed pods, which resemble a row of cigars. Children frequently used the dried pods in games.
- Urban and Rural Plantings: In the late 1800s and early 1900s, catalpas—especially northern—were promoted for systematic planting along roads, farms, and urban parks.
What others are reading
The trees’ showy flowers and unique seed pods make catalpas a distinctive visual feature in historic towns and cemeteries.
Value to Wildlife and Ecology
- Catalpa Sphinx Moth (Ceratomia catalpae): The larval caterpillars rely exclusively on catalpa leaves for food and attract various bird species as a food source.
- Pollinators: The flowers attract bees, hummingbirds, and other pollinators during the blooming period.
- Cavity-Nesting Birds: Older catalpa trees can develop hollows that serve as nesting sites for squirrels, owls, and songbirds.
- Host for Rich Insect Life: The shade and shelter provided by large leaves offer refuge for insects and beneficial spiders.
While the large leaves and fallen pods can be messy in yards, the ecological value and beauty of mature catalpas are significant.
Frequently Asked Questions (FAQs)
Q: How can I tell if my catalpa tree is northern or southern?
A: Check the size and hairiness of the seed pods and seeds (northern’s are longer and more fringed), leaf size (northern’s are larger), and the bark texture (northern is more furrowed, southern exfoliates in thin scales). Flowers on northern catalpa are typically larger and have fewer spots.
Q: Where are catalpa trees native?
A: Northern catalpa is native to parts of the Midwest and lower Midwest; southern catalpa is native to the deep Southeast United States. Both have become widely distributed by planting.
Q: Are catalpa trees good for urban environments?
A: Yes, their tough nature, tolerance for poor soil, and showy flowers make them useful as ornamental or shade trees in urban parks and yards, provided there is enough space for their spreading roots and large leaves.
Q: What are catawba worms, and why are they important?
A: Catawba worms are the caterpillar stage of the catalpa sphinx moth. They are highly valued as fish bait in the southern states and have a long history of use among fishermen and in rural folklore.
Q: Are there any drawbacks to planting catalpas?
A: Fallen leaves, flowers, and pods can be messy, and infestations of catawba worms can defoliate the tree temporarily. However, the tree usually recovers, and its wildlife value is substantial.
Conclusion
The enduring charm and unique utility of the northern and southern catalpa trees make them memorable elements of the North American landscape. Whether enjoyed for their striking blooms, role in local ecosystems, or place in folk traditions, catalpas stand out among native trees—a living connection to both the wild and cultivated past of our communities.
References
- https://a-z-animals.com/blog/northern-catalpa-vs-southern-catalpa/
- https://extension.illinois.edu/blogs/hort-home-landscape/2015-06-12-plant-week-catalpa
- https://www.finegardening.com/article/catalpa-trees-catawba-worms-and-southern-lore
- https://caseytrees.org/2014/07/tree-month-catalpa/
- https://gobotany.nativeplanttrust.org/species/catalpa/speciosa/
- http://treenotes.blogspot.com/2008/06/northern-and-southern-catalpas.html
- http://feridasbackyard.blogspot.com/2010/08/catalpa-pros-and-cons.html
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