You may know it as Catalpa, Catawba, Indian Bean, Cigar Tree or Fish Bait Tree, but chances are if you live in the United States, you have seen this unique tree. Catalpa is a true tree of the people, surviving in all kinds of conditions from polluted cities to windswept prairies. Native Americans utilized the Catawba long before settlers arrived in the New World, but the settlers soon recognized the value of the Catalpa and carried it with them across the country. With Catalpa's ability to survive most conditions and grow rapidly, and its bonus of beautiful, fragrant flowers, it was the pioneers' choice of trees to plant on a new homestead.
There are two recognized species of Catalpa or Catawba tree in North America: Southern Catalpa, C. bignonioides, and Northern Catalpa, C. speciosa. There are only subtle differences in the two, and they have both been planted far outside their natural ranges. Both Catalpas are hardy from Zones 4 to 8, both have large, heart-shaped leaves, fragrant white flowers splashed with yellow and purple and long, skinny seed pods resembling bean pods. The Southern Catalpa is said to be a slightly smaller tree, with the leaves growing in a whorled pattern rather than opposite each other as in the Northern Catalpa. The leaves of some Northern Catalpas may be lobed.
The flowers of the Catalpa tree are large, frilly and orchidlike. They are marked with purple dots and yellow patches; no two seemed to be marked quite alike. When Catalpa trees bloom in June or July, the sweet scent of the flowers can be almost overpowering. Bees, butterflies and hummingbirds flock to the flowers. It's quite a show for a week or two, then all of the flowers are shed, making the ground under them look like a summer snowfall has occurred. The flowers turn into purple, then green, then brown narrow pods, up to a foot long. They may hang in the trees all winter. In the fall or the following spring, the pods release hundred of flat seeds. If birds do not eat them, they turn into more Catalpa trees in every corner of the yard.
The Catalpa tree is slow to leaf out in the spring, but when it does, it produces a deep shade. The leaves of catalpa are large, up to a foot long in some cases. Usually they are medium green, slightly lighter and downy on the underside. Purple- and golden-leaved varieties exist.
While Catalpas seem to pop up everywhere when you have a tree in the yard, the seeds seem to be a little tricky to germinate indoors. If you cannot find a small Catalpa tree to purchase and have access to seeds, my advice would be to sow them in an outside bed of well-prepared soil in late fall or very early spring, cover lightly and let nature do the work. Catalpas transplant fairly easily when small. Catalpas will grow almost anywhere, in any kind of soil, but they need full sun and fairly regular moisture. They will not grow in poorly drained areas. They grow quite rapidly when young. A Catalpa tree in a good spot may add two feet of growth a year, and trees bloom young, as early as six years of age.
Catalpa trees provide shade and wood that is strong and straight, good for fence posts or woodworking, with an interesting grain. Catalpa trees do have some disadvantages in the home landscape, however. The trees are messy, shedding flowers, large leaves and seed pods abundantly. Some people are allergic to the pollen of Catalpa flowers and the scent really bothers some sensitive people. In the South Catalpas are also host to large green-and-yellow caterpillars in great numbers, the larvae of the Catalpa Sphinx moth. To some people this is actually an advantage; the caterpillars are excellent fish bait, the reason for one of Catalpa's folk names. Many a southern fisher has planted Catawba trees just to get the bait worms. But for other folks, these caterpillars are a big disadvantage, raining down green droppings and defoliating the trees. They can be controlled with insect sprays when they first hatch.
Catalpa trees often become infected with Verticillium Wilt, a fungal disease that causes large parts of the tree to die. Catalpas tend to shoot up suckers from the roots and side shoots from the trunk, and few ever totally die, but they look unsightly and need constant trimming of dead areas. There is no real cure, but fertilizing with a high-nitrogen fertilizer helps the tree keep growing. If you remove the tree, don't replace it with another Catalpa tree in the same area as the disease remains in the soil.
Both the Northern and Southern Catalpa are sometimes offered in nurseries. A purple-leaved and a golden-leaved variety are occasionally seen. Catalpa ovata, Chinese Catalpa, is a smaller-size tree with lobed leaves. The creamy yellow flowers are also a bit smaller and produced later in the summer.
For fast shade in rough conditions, Catalpa is a good choice. Farmers plant Catalpa for the wood, which makes strong, lightweight rot-resistant fence posts. It makes a nice specimen tree with showy flowers at a time few other trees are blooming. Fishers plant Catawba because it attracts caterpillars used for bait.
If people in the household frequently suffer from seasonal allergies, a Catalpa tree might not be a good landscape choice, as the flower pollen is quite allergenic. The roots of Catalpa are poisonous. The sawdust from working with Catalpa wood can cause inhalant- and skin-allergy symptoms. For that reason, it would not be good to use catalpa wood chips or shavings as animal bedding. The seedpods and seeds of catalpa contain a mild narcotic and sedative and should not be put in the mouth or consumed.
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