The Fascinating Catalpa Tree That Looks Like It Has String Beans

The catalpa tree is an ornamental shade tree that is easily identifiable by its long, hanging seed pods that resemble string beans. With its large, heart-shaped leaves and showy spring blooms, the catalpa is a unique addition to any landscape. But it’s the dangling bean-like pods in fall and winter that give this tree its distinctive legume-like appearance.

An Overview of Catalpa Trees

Catalpa trees belong to the genus Catalpa and the family Bignoniaceae They are native to warm temperate regions of North America, the Caribbean, and East Asia. The two catalpa species commonly grown in the US. are the northern catalpa (Catalpa speciosa) and the southern catalpa (Catalpa bignonioides).

Catalpas are fast-growing, deciduous trees that typically reach heights between 40 and 60 feet. They have spreading branches that form an oval-shaped canopy up to 40 feet wide. The large leaves grow in whorls of three and can measure over 10 inches long and 8 inches wide.

One of the most ornamental features of catalpa trees are the spring blooms. The showy flowers emerge in late spring in clusters of white or yellow. The funnel-shaped flowers have ruffled edges and purple dotted markings on the inside.

But what catalpas are really known for are the long, slender seed pods that hang down from branches in fall Resembling green beans, the pods grow from 1 to 2 feet long! Inside the pods are small winged seeds that disperse when the pods split open

The Bean-Like Seed Pods

The hallmark feature of catalpa trees that gives them the appearance of dangling string beans are the elongated seed capsules These bean-like pods develop from the flowers and contain catalpa seeds.

The seed pods start off green and turn brown as they mature in early fall. Northern catalpa trees (Catalpa speciosa) have the longest pods, growing up to 24 inches. Southern catalpas (Catalpa bignonioides) have slightly smaller pods reaching around 1 foot long. Depending on the species, the narrow pods can look like extremely long green beans, broad beans, or even black-eyed peas!

Catalpa seed pods hang down in clusters, persisting on the tree throughout fall and winter. The visual impact of the dangling brown pods is eye-catching. As the common name ‘cigar tree’ suggests, the drooping pods look like brown cigars hanging from bare winter branches. The pods gradually split open to release the winged catalpa seeds inside.

Why Do Catalpa Pods Look Like Beans?

The legume-like appearance of the catalpa seed pods is an evolutionary adaptation. The elongated capsule shape allows the papery, lightweight seeds to be widely dispersed by the wind.

When the pods mature and crack open in early winter, the winged catalpa seeds are carried away on the breeze. This ensures the seeds are scattered far from the parent tree to give seedlings the best chance of flourishing.

The species name ‘bignonioides’ refers to the resemblance of the seed pods to beans in the genus Phaseolus. Other common names for the southern catalpa include ‘cigar tree,’ ‘Indian bean tree,’ and ‘bean pod tree’. All these names draw attention to the conspicuous bean-like pods.

Growing Catalpa Trees for the Pods

Catalpa trees are easy to grow and care for. They tolerate most soil types, growing well in moist, well-draining soil. Although they prefer full sun, they can cope with partial shade. Once established, they are also drought tolerant.

To add visual interest to your garden from late summer to winter, plant a catalpa tree. The seed pods will provide texture and a talking point as they dangle like green beans from the branches.

If you don’t want to wait years for a catalpa tree to start producing the prized bean-like pods, start your own from seed.

Follow these steps to grow your own catalpa tree with hanging bean pods:

• Collect ripened catalpa seeds in early fall. Allow seeds to dry then store in the refrigerator over winter.

• In spring, plant catalpa seeds in pots indoors. Cover with 1” of potting soil and keep moist.

• When seedlings are 3-4” tall, transplant into larger pots and grow outside.

• The following spring, plant catalpa seedlings into your garden. Choose a spot in full sun.

• Water young trees regularly until their root system establishes. Then water occasionally during drought.

• Add a 2-3” layer of mulch around the base and fertilize in spring and summer.

• Prune only to remove damaged branches.

• Bean-like pods will develop after around 5 years. Pick a few to display indoors.

Growing catalpa trees is highly rewarding. As well as the ornamental pods, you’ll have fragrant spring blooms, lush large leaves, and yellow fall color. The large catalpa leaves also make these excellent shade trees.

Attractive Features of Catalpa Trees

Here is an overview of the defining features of catalpa trees through the seasons:

Spring

• Clusters of showy, trumpet-shaped white flowers with purple and yellow markings. Very fragrant smell.

• Large light-green heart-shaped leaves emerge in whorls of 3.

Summer

• Dense, lush oval canopy provides dappled shade.

• Leaves are up to 12” long and 8” wide.

Fall

• Leaves turn yellow or brown before dropping.

• Slender seed pods grow up to 2’ long. Pods are initially green maturing to brown.

Winter

• Picturesque bare tree with dangling bean-like pods. Pods persist through winter.

All Year

• Fast growing tree matures between 40 – 60 ft. tall and up to 40 ft. wide.

• Smooth gray bark becomes fissured with age.

• Low maintenance and easy to grow in most conditions.

Catalpa Tree Symbolism

The catalytic tree is rich in symbolism and historical meaning.

To Native American tribes, the bean-like seed pods represent the ‘winged head’ of a catalpa worm moth. Some tribes smoked the wood believing it had hallucinogenic effects.

Catalpa wood is associated with endurance, determination and strength. It was traditionally used to make fence posts and railroad ties, as the hard, durable timber withstands weathering.

In the Victorian era, catalpa trees were prized for their ornamental value and planted for their showy blooms. The tropic-looking leaves and exotic seed pods brought a sense of the exotic to parks and gardens.

Today, catalpa trees continue to enhance gardens with their bursts of spring color, broad leaves, and swinging bean pods. If you have space to accommodate their spreading size, plant a catalpa for a talking point all year round.

Frequently Asked Questions About Catalpa Trees

Here are answers to some common catalpa tree questions:

Are the seed pods on catalpa trees edible?
No, catalpa seeds and pods are not edible. They have no nutritional value or distinct flavor.

What is the best time to prune a catalpa tree?
Prune in late winter before growth restarts. Only remove damaged, diseased or crossing branches.

How fast do catalpa trees grow?
Catalpas are fast growing trees, averaging 1-2 feet per year. They reach mature heights between 40 and 60 ft.

Where is the best place to plant a catalpa tree?
Plant catalpas in full sun for best growth and flowering. They tolerate most soil types except permanently waterlogged conditions.

Should I pick the bean pods on my catalpa tree?
Leave some of the pods over winter for visual interest. You can pick a few seed pods in fall to display indoors in a vase.

Is the catalpa tree messy?
Catalpas drop large leaves and seed pods so do create mess. Plant away from footpaths, seating areas, pools etc.

Are catalpa trees susceptible to diseases?
They can be affected by verticillium wilt and powdery mildew but are generally robust, healthy trees.

The Captivating Catalpa Tree

The catalpa tree may not be the prettiest or the most fragrant flowering tree, but it certainly has character. With its oversized, exotic-looking leaves, vibrant spring blooms, and curiously bean-like seed pods, the catalpa is an eye-catching garden specimen tree.

If you have the space to accommodate their generous proportions, catalpa trees create wonderful architectural elements in a garden. The beautiful heart-shaped leaves cast dappled shade in summer then turn golden yellow in fall. Fragrant spring blossoms are a bonus. But the pièce de résistance is undoubtedly the dangling green seed pods that will have people looking twice!