The catalpa tree is an attractive ornamental shade tree that has the added benefit of producing fish bait. I recently set my mind to find one to use as a source for bait, and to write about in this blog. Unexpectedly, the only catalpa tree I could find in my area was a large one on a busy street in Lithia Springs, Georgia. It was planted years ago next to a store that is no longer there. It was an attractively shaped shade tree with beautiful clusters of white tubular flowers. The odor of the flowers was pleasant, much as you would experience walking into a florist shop. I was very happy finding this tree and also several younger trees on the lot, but I was disappointed to not find fish bait also.
The tree I found was a Northern catalpa, Catalpa speciosa. I knew this because crushing the leaves produced no bad odor as would happen if it was a Southern catalpa, or Catalpa bignonioides. The Northern 
catalpa is less irritating to those sensitive to the tree’s chemicals, and is most often preferred to plant as an ornamental. The catalpa tree is also known as catawba tree, bean tree, cigar tree, caterpillar tree, worm tree, fisherman’s tree, fish bait tree. The catalpa tree, which is native to North America, got its name from Native American Indians who used the tree.
Catalpa trees can grow 4 feet in a year under ideal conditions of full sun and well-drained soil. Older trees grow slower. Trees may grow to 70 feet. The catalpa tree I found was 40 to 50 feet tall with a spread as wide. It was probably 40 or 50 years old. The young catalpa 
trees I found had larger leaves and grew in a thicket, appearing invasive in nature. Bark on the young trees appeared thin, but on the older tree the bark was separated into irregular fissures with gray-brown scales. 
Interestingly, twigs have nodes of three sunken leaf scars which are grayish- brown and resemble moon craters. Buds are small and slightly hairy. Leaves are opposite, or whorled with 3 per node. They are simple, 6 to 12 inches long and 4 to 9 inches wide. They are heart shaped at the base, and connected to the stem by a petiole almost as long as the leaf. Leaves are smooth and green on top and downy and lighter green underneath. Fall color is yellow-brown and duration is brief. The large leaves make the tree valuable as a shade tree.
Catalpa flowers appear on trees from May through July, and they have a pleasant fragrance. They are perfect, having both male and female parts. Flowers have bell-shaped corollas of 5 lobes. The flowers are showy, with the 5 petals in each flower being up to 1 ½ inches long but unequal in size. They are 
white with purple spots and orange stripes at the throat. The coloration and positioning of the petals appear perfect to draw pollinators. The flowers are in branched, upright clusters. Fruit are seedpods that are slender and green in the summer and brown in the autumn. They grow 6 to 24 inches long and ½ inches wide, and appear much as cigars. They split open 
lengthwise in autumn to release seeds. Southern catalpa seeds are more pointed than northern catalpa seeds. Seeds are about 1 inch long, 1/3 inches wide, are flat, and have a light brown coat and wings. The wings are rounded at the ends, terminating in a tuft of short hairs. Seedpods generally stay attached to the tree over winter, and give the tree an interesting appearance.
The wood of the catalpa tree is moderately light in density. It has pale gray sapwood and grayish brown heartwood. It has no characteristic odor or taste. It is coarse– grained and ring porous, and soft. It is not strong, but due to the toxins it contains it is very durable when used as fence posts. It is excellent for carving and boat building.
The catalpa tree has a special relationship with the catalpa sphinx moth, which only eats catalpa leaves. Beginning after flowering, caterpillars of the moth appear and strip leaves from the tree several times each year, and the tree recovers quickly each time to produce more leaves. Often all life cycles are present on the tree at once, but rarely does caterpillar damage kill the tree. When caterpillars are ready to pupate, they crawl into the soil to do so. When they emerge as moths, they return to the leaves to lay eggs that produce more caterpillars and the process goes on. Leaves under attack secrete more nectar than normal, attracting various ants, beetles and insects that help by feeding on the caterpillars. One natural enemy the nectar helps attract, the braconid wasp, lays eggs beneath the skin of 
the caterpillars, and the developing larvae feed on the host until ready to pupate. The caterpillar is being eaten alive, but parts are being eaten that are not essential. Only when the caterpillar becomes overloaded with feeding larvae does it die. Often, a heavy season of wasps or other predators will wipe out catalpa caterpillars on a tree. If catalpas are desired on the tree, some may be replaced from another tree.
Catalpa caterpillars make good fish bait, for all types of fish. They are most often referred to as “catalpa worms”. They do not sting or bite, but you may feel suction appendages trying to hold on to you that normally help them hold on to leaves. They may be put on the hook as you would a worm. Some people cut (or bite!) the head off, and using something like a match to push it from the end, it can be turned inside out to expose the delicious innards to the fish. The catalpa caterpillar is tougher than a worm or cricket, and several fish may be caught with only one. The caterpillars are lively, and must be kept in a cage or other closed container to keep them from crawling away. They may be stored for weeks in the refrigerator in a container until needed, by layering them with catalpa leaves and corn meal. They may be frozen this way also, becoming active again when thawed. Fish will like them whether or not they survive this process.
The catalpa tree is a great tree that can be used not only as an attractive ornamental shade tree, but for fish bait. However, neither use is without problems. Seed pods, flowers and fall leaves litter the yard, and the shade is too dense to grow anything under it. The tree can produce good fish bait, but when the fish bait strips the tree of leaves, the tree loses attractiveness. Caterpillars can be heard munching on the leaves. The shade of the tree is not enjoyable when droppings and caterpillars are falling on you, and you are smashing caterpillars as you walk. The tree would be more enjoyable planted in parks, large lots, or near fishing areas. Where it is thoughtfully placed, the catalpa tree is sure to be enjoyed.