The umbrella catalpa tree (Catalpa bungei) is a deciduous tree native to China and other areas of Eastern Asia. It has a rounded shape and flowers that range in colour from white to pink when it blooms in summer. It grows to 30 feet tall and will tolerate cold temperatures as low as minus -3.89 degrees C. Its water needs are low to medium, according to the PNM power company of New Mexico.
Starting From Seed
It's possible to grow a catalpa tree from seed if collected from an existing tree and used as soon as possible. Cold stratification helps them to germinate. Three weeks in your freezer is sufficient. Plant stratified seeds in pots in spring, keep the soil moist, and then transplant seedlings to a cold frame or other protected area when they are large enough to prick out of the growing medium. Leave them in the protected area until the following spring when you can transplant young trees to the garden.
The umbrella catalpa tree is not particular about the soil in which it grows. Catalpa trees grow in sandy, loamy or clay soil that is acidic, neutral or alkaline, making it adaptable to most environments. However, it grows best when the soil remains moist. Although it tolerates smog and other types of air pollution, it prefers protection from heavy winds. If your region has hot summers, this tree will do well. Protect young trees from frost in late spring: if you plan to plant a sapling tree, wait until the threat of frost has passed.
The Oregon State University Extension website states that severe pruning is appropriate for catalpa umbrella trees. Prune this tree during its winter dormant season, after all leaves have dropped. When you prune a plant severely, you control its shape and appearance by cutting off lower branches, shaping it into a globe or other shape and allowing sufficient sunlight to enter the central region of the plant. Always prune dead or broken branches and any that appear diseased. Prune all branches that cross over or touch each other.