catalpa
( kuh - TAL - puh )
At-A-Glance InformationThis genus of deciduous trees (also called Catawba) needs full sun to light shade and moderate to regular water for best performance. Leaves are large and heart-shaped, flowers give the tree a tropical look. Flowers are commonly white, marked with yellow or soft brown, and are followed after blooming in spring and summer by inedible, elongated seedpods that are sometimes called 'Indian Beans'. Catalpa trees are native to warm temperate and subtropical regions of North America, the Caribbean, and East Asia. Trees can be a bit messy; flowers and seed capsules can make for a bit of clean up. Use these trees as specimens, lawn or shade trees, or as beautiful additions to beds and mixed landscapes. Take care when planting these trees in the landscape, as the roots are highly poisonous if ingested.
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Catalpa Species and Varietals
The genus Catalpa includes 8 species and is a member of the plant family Bignoniaceae. The genus name is derived from the Muscogee name for the tree (Kutuhlpa), which means 'winged head' (referring to the winged seeds). Catalpa trees grow well in zones 3-10 and 14-24, though this varies somewhat depending on the species grown. To find your zone, click here: Zone Map.
Catalpa bignonioides (Common Catalpa, Indian Bean, Cigartree, Southern Catalpa)
This species is native to the southeastern United States and reaches 30-40 feet tall and about as wide. It is resistant to Oak Root Fungus, but does not tolerate alkaline soils well. The species and its varieties listed below are commonly used as street and shade trees.
This species is native to the southeastern United States and reaches 30-40 feet tall and about as wide. It is resistant to Oak Root Fungus, but does not tolerate alkaline soils well. The species and its varieties listed below are commonly used as street and shade trees.
Catalpa bungei (Manchurian Catalpa) Reaches 25 feet tall with a pyramidal shape. Flowers are purple and spotted with white and pink. These trees are native to China, and the species is named for botanist Alexander Bunge. |
Catalpa fargesii (Chinese Bean Tree) This native of China reaches over 80 feet tall at maturity, and produces white to pink or purple flowers in abundance in spring and summertime. Blooms commonly have darker markings and yellow staining towards the center. Leaves are downy on their undersides, and foliage is green. |
Catalpa speciosa (Northern Catalpa, Hardy Catalpa, Western Catalpa, Cigar Tree, Catawba) Best when grown in zones 2-24 and natie to the central United States. This is a commonly grown species of Catalpa in the Western United States and reached 40-60 feet tall and 20-40 feet wide. It has a rounded head and leaves that reach up to a foot long (they are odorless when crushed). |
Caring for and pruning catalpa Trees
Plant Catalpa in a place in the landscape that receives at least 6 hours of sun each day. These trees can tolerate partial shade, but too much shade can lead to fewer blooms. These adaptable trees can grow in a variety of soils, including sandy, loamy, and clay soils. They do like a lot of nutrients, and prefer soil to be rich and well draining. If soil is particularly low in nutrients, it is a good idea to amend the planting area with plenty of compost before installing the tree. Catalpas do well in soils that have a pH range of between 6.0 and 7.5. Water young trees regularly, especially during warmer times of the year, to help them establish a strong root system. Mature trees are a bit more drought-tolerant, but still appreciate occasional deep waterings, especially in summertime. Avoid overwatering these trees, as they do not tolerate wet feet well, and will develop root rot problems.
Fertilize Catalpa trees once a year by incorporating organic material around the base of the tree to improve soil fertility and structure. If trees seem to be struggling, they may benefit from an early springtime feeding with a balanced (such as a 10-10-10), slow-release fertilizer to support growth and flowering. Protect trees (especially young ones) from strong winds, which can damage the foliage. Shape plants when they are young, and shorten side branches as the tree grows. When branching has started at the desired height, remove all lower branches to establish a clean canopy. Once established, simply head back or thin out branches that make the tree look unbalanced. Otherwise, a yearly clean up and removal of dead, damaged or diseased plant material is sufficient.
Fertilize Catalpa trees once a year by incorporating organic material around the base of the tree to improve soil fertility and structure. If trees seem to be struggling, they may benefit from an early springtime feeding with a balanced (such as a 10-10-10), slow-release fertilizer to support growth and flowering. Protect trees (especially young ones) from strong winds, which can damage the foliage. Shape plants when they are young, and shorten side branches as the tree grows. When branching has started at the desired height, remove all lower branches to establish a clean canopy. Once established, simply head back or thin out branches that make the tree look unbalanced. Otherwise, a yearly clean up and removal of dead, damaged or diseased plant material is sufficient.
Propagation
Catalpa can be propagated either by using cuttings or from seed. To ensure that your propagated plant will have the exact same qualities and characteristics as the parent plant, use the cutting method. If you would like to experiment and see what plant you can grow from seed, just keep in mind that it will not necessarily be the same as the parent plant. To propagate your tree, follow the instructions below:
Propagating Catalpa by Cutting
Propagating Catalpa by Seed
Propagating Catalpa by Cutting
- Gather your materials. You'll need a clean, sanitized, sharp pair of garden shears, rooting hormone, a pencil, and a 3-inch pot filled with well-draining compost or other organic material. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand.
- In spring or early summertime, choose the plant that you'd like to propagate. Ensure that this plant has had a good watering the night before, as this will improve the chances your cutting will take root. Cut one or more 6 inch portion(s) of the end of a non-blooming branch and strip the leaves off of the lower half. Make a hole in your planting medium by pushing your pencil into the soil. Dip the end of the stem in rooting hormone, and plant it in your pot. Fill in soil around the cutting to support it, but do not pack it down too much.
- Moisten with water, and ensure that the pot has good drainage. Your pot should be kept in warm, sunny conditions indoors (and not in direct sunlight). Water whenever your soil is dry under the top layer. After about four to six weeks have passed, your cutting should be rooted. When you notice new growth, you'll know you have roots.
- Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring, when you can transplant it to its new home. Ensure that the last frost of the year has occurred before doing this, as it can seriously damage your new shrub.
Propagating Catalpa by Seed
- Keep in mind that the plant you get from seed will not necessarily mimic all of the characteristics of the parent plant. To propagate by seed, you will need a paper bag, a pot or tray filled with well-draining compost or other organic material, a spray bottle and a fork. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand. You will also, after a few weeks, need individual 3-inch pots for each seedling that grows.
- Harvest your seeds. The seed pods on Catalpa plants are pretty easy to spot, they're large and dangle from the branches, left behind after flowers have faded. Once they have dried out and begun to split open, you can harvest the seeds inside. Cut them off of the plant, placing them in a paper bag. Harvest as many as you can, and place the paper bag in a dry, cool, dark area. They will begin to split open and release the seeds contained inside. Once they have been released, take them out of the bag and put them in a container so you can work with them.
- Water your prepared seed tray or pot filled with soil, and ensure that good drainage is occurring. Place your seeds in your prepared pot or seed tray about a quarter inch to a half-inch under the soil surface. Cover them with soil and water with your spray bottle. Place your tray of seeds in a warm area that receives bright, indirect light. A greenhouse is the most ideal climate, but a planting tray inside a window will do as well. Germination usually takes 14 days from sowing. Once you begin to see seedlings sprout and they are able to be handled, transplant them to their own individual 3-inch pots, filled with the same potting medium as described in Step 1. Loosen the seedlings from the potting medium by digging down with the tines of your fork about an inch and a half, gently working the seedling up until it is out. Then, replant the seedling in its individual pot.
- Keep the seedling's potting medium moist, but not wet, by spraying the soil with your spray bottle. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring (after the danger of frost has passed), when you can transplant it to its new home.
Problems and Pests
These trees sometimes have issues with the following pests and diseases:
- Catalpa Sphinx Moth Caterpillars
- Verticillium Wilt
- Leaf Spot
- Powdery Mildew
- Catalpa Hornworm
- Japanese Beetles
Gallery
Videos
Lean all about Catalpa trees.
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All you need to know about Cigar Trees.
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Learn about Northern Catalpa.
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How to grow these beautiful trees from seed.
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Resources
The New Sunset Western Garden Book: The Ultimate Gardening Guide (2012) - Page 225, Catalpa
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