This tree belongs to the Bignoniaceae vine family, and is often referred with names like catawba tree, cigar tree, or fish bait tree. Native to temperate zones of North America, the Caribbean, and eastern parts of Asia, this tree has two well-known species -- Southern Catalpa (or Catalpa bignonioides) and Northern Catalpa (or Catalpa speciosa). The appearance of both these species is more or less similar except that the leaves, bean pods, and flowers of Northern Catalpa are slightly larger than that of Southern Catalpa.
The catalpa is a deciduous tree having a height and width of 12-18 meters and 6-12 meters respectively. These trees can be easily identified by their large leaves which can grow as big as one foot in length and are shaped like a heart. Apart from the normal green-colored leaves, there are some varieties which have purple and golden color leaves as well.
Catalpa trees bloom in the month of June and July. The flowers are 2 inches long and 3 inches wide with white-colored petals having yellow blotches and purple dots on them. The sweet fragrance attracts bees, butterflies, and hummingbirds. Usually, the flowers stay on the tree for a week or two.
Fruits can be seen in autumn and they look like narrow bean pods. They are brown in color and the size may vary from 8-12 inches. They contain large number of small, flat seeds. The pods remain on the trees throughout winter. With the onset of spring, seeds within the pods are released and are dispersed by wind in the surrounding areas, from which new trees grow.
Their basic requirements are full sun and a well-drained soil. Prior to sowing the seeds, loosen the soil to about six meters diameter and add nitrogen rich fertilizer to it. Now place few sprouted seeds four inches deep. Water the seedling well so that a strong root can develop.
Side shoots tend to develop from the main trunk of the tree. Sometimes, they die on their own. Others should be trimmed regularly. These trees get infected by Verticillium Wilt, a fungal disease that can lead to death of the affected parts. There is no cure for this problem. Removal of the dead parts by pruning and application of nitrogen rich fertilizer keeps the tree healthy. Usually, it starts blooming at the age of six years. These trees do not grow well indoors.
You should not grow this variety in your garden if any member of your family suffers from seasonal allergies. This is because the pollens of its flowers often act as allergens. The roots of are mildly poisonous in nature and should be handled with care. The seeds should not be consumed as they have a small amount of narcotic content.