Catalpa Tree Facts, Uses, and Planting Tips

The catalpa tree is an ornamental shade tree that produces dense clusters of white flowers and long seed pods. They can grow upwards of 70 feet in height, although more realistically, they typically grow to be around 50 feet.

There are three common catalpa species—two North American and one Chinese:

1. Northern Catalpa (Catalpa speciosa): Native to the midwestern United States
2. Southern Catalpa (Catalpa bignonioides): Native to the southeastern United States
3. Chinese Catalpa (Catalpa ovata): Native to western China

Because they are hardy plants that require very little water, various species are often grown outside of their native regions—particularly for their decorative features.

Catalpas are also deciduous trees, meaning they shed their leaves annually—usually in the fall or after the first frost. During this time, they also shed their long seed pods and flowers, which can deter some people from growing the tree.

Catalpas are mainly used for their ornamental features.

They make excellent decorative plants for large areas including yards and parks. The large size and broad, heart-shaped leaves also make them great shade trees.

Some of its more notable attributes are the flowers and bean-like pods. Come springtime, beautiful and fragrant clusters of white, trumpet- or bell-shaped flowers cover the tree. The flowers resemble an iris, with its purple and yellow coloration on the inside. The fruits, which resemble green beans, hang down from the branches and provide another visually intriguing feature.

The "beans" have no known nutritional or savory qualities.

Although the fruits resemble bean pods (hence the name "Indian bean tree"), they're not usually eaten.

That being said, they are used in traditional medicine as treatments for ailments ranging from skin infections to conjunctivitis to asthma, although there is no scientific evidence backing these claims. According to the USDA, seeds and pods were used by pioneers in the 19th century to treat asthma, whooping cough, and various heart diseases.

Teas and poultices made from the bark and leaves are often used in herbal medicine as laxatives and mild sedatives, and to treat skin wounds and abrasions, infections, snake bites, and even malaria. There is also some scientific evidence for the diuretic properties of Catalpa fruits (pods and seeds).

Although the fruits, bark, and leaves are considered safe, according to The Encyclopedia of Medicinal Plants by medical herbalist Andrew Chevallier, the Catalpa roots are highly poisonous. Therefore, herbal preparations should be handled by or under the guidance of a specialist.

You can grow a catalpa tree from cuttings, but it's easier to grow them from seeds.

1. Collect the pods and store them in a cool, dry area.

Collect the pods after the leaves fall—once the pods are sufficiently dried but before the seeds have fallen from open pods. Store the pods in a cool, dry area. When you're ready, the seeds may be separated from the pods and placed in packets.

2. Plant the seeds in a pot with good drainage.

Catalpa trees grow best with low moisture, so make sure the pot or ground soil has good drainage.

Fill the pot with potting soil (pH 5.5–7) and place a few seeds on top. Lightly cover the seeds with more potting soil—no more than 1 inch in depth.

If you choose not to grow them in a planter then plant the seeds in the spring in warm, loose, and rich soil.

3. Lightly water the seeds, and place the pot in a shaded area.

The young seedlings won't be able to handle the intensity of full sunlight yet, so keep them in a shaded area with mild temperatures (60–70 ºF).

Continually monitor the seedlings and keep the soil moist but not soaked.

4. Transplant the seedlings to progressively larger pots.

Within a couple of months, the seedlings will be a few inches tall with one or two leaves. You can certainly transplant them to the desired permanent location, but it is recommended to continue growing them in pots over the first winter. This makes it easier to care for the young plant and prevent weeds, pests, and diseases from damaging it.

Use fresh potting soil each time to ensure the plant gets enough nutrients. No fertilizers are required.

5. Transplant the catalpa tree into your garden or lawn.

Spring is the best time to move the young catalpa to its permanent home. Choose a location that receives full sunlight or only partial shade.

Again, the soil should be slightly acidic and have good drainage. Dig a hole that's a little larger and wider than the pot the seedling is in. Remove any roots, weeds, or other debris.

Carefully remove the seedling and place it in the hole. As you cover the roots with soil, adjust the roots so that they point outwards and downwards. This ensures healthy growth and prevents the roots from surfacing in the future.

Continue watering the young tree—just enough to keep the soil moist. Applying mulch can help retain moisture and prevent weeds from sprouting.

Mess and Potential Damage

Despite their beauty and intrigue, catalpa trees are large and messy. For these reasons, be mindful of the area that the roots and branches can cover. Avoid planting catalpas near buildings, fences, sidewalks, and plumbing or electrical lines.

The tree sheds heavily in the fall and winter, littering the leaves, flowers, and seeds over sidewalks, driveways, and cars. Regular maintenance is required to keep the mess under control.

Pests

The catalpa sphinx caterpillar (Ceratomia catalpae) is the main pest, whose larvae eat through the leaves. Although a catalpa tree can tolerate this, if the caterpillar population isn't controlled, consecutive generations of larvae can completely rid the tree of leaves and kill it.

Other pests include rabbits that can chew through young stems and grubs that eat young seeds.

Diseases

If you notice that the leaves are covered with a white, powdery substance, the tree may have powdery mildew. If this is isolated to certain branches or areas of the tree, you can prune these parts to prevent the fungus from spreading. Spraying fungicides or a natural alternative can also help control the disease.

Another fungal disease that can affect catalpas is verticillium wilt. The fungus invades the root system and clogs up the vasculature, cutting off water supply and causing branches to die off. Leaves may turn yellow and brown before falling off. The symptoms are similar to dehydration, but more watering will not solve the problem. Applying fungicides at the roots and/or increasing the nitrogen concentration in the soil may help.