Problems With a Catalpa Speciosa

Northern catalpa (Catalpa speciosa) is a large-leaved, deciduous tree that grows up to 50 feet, producing a loose, irregular habit, showy panicles of white or lavender, bell-shaped flowers and narrow pods up to 18 inches long. Though tolerant of less-than-ideal growing conditions, northern catalpa is considered a problematic tree by many due to its ragged appearance, disease susceptibility and tendency to drop litter.

Northern catalpa is susceptible to verticillium wilt, a soil-borne disease that causes leaves to curl and wilt and entire branches or trees to die. Removing bark from the branches may reveal irregular streaking in the wood. Fungicides are not effective, and soil fumigants are not practical for most homeowners, according to the University of Minnesota Extension. Improved cultural care may help combat the disease in its early stages. The tree may also develop foliage diseases such as brown fungal leaf spot, though this is not usually serious.

Northern catalpa tends to look ragged by the end of the growing season, as the tree's large leaves are often tattered due to hail, wind and foliage-feeding insects. Fall color is not considered showy. Sphinx moths commonly use the tree for a larval host and can cause foliage damage, though control is not usually warranted, according to the University of California Statewide Integrated Pest Management Program. Trees have brittle branches that break easily, disrupting the form of the tree.

North catalpa can create a serious litter problem, especially if it is planted near a walkway or patio. Dropped flowers become slimy and brown on the ground, and pods can accumulate to create a mess that is slow to deteriorate if not swept up. However, pods are formed in abundance only every two to three years, according to the Missouri Botanical Garden. Leaves fall throughout the growing season, creating a never-ending source of debris. This is especially true if sphinx moth caterpillars are present.

To help keep your Northern catalpa in good health and looking its best, irrigate regularly throughout the growing season. Well-irrigated trees are less likely to develop verticillium wilt. Do not plant the tree where wilt is known to be present in the soil. Do not use chipped branches infested with verticillium as mulch. Northern catalpa is best in a moist, fertile soil in full or partial sunlight in U.S. Department of Agriculture plant hardiness zones 4 to 8.