Northern Catalpa (Catalpa speciosa)

A deciduous tree from the Bignonia Family (Bignoniaceae)

Northern Catalpa, native to a relatively small area of the central Mississippi Valley basin, has been extensively cultivated in Ohio for over 200 years, and is now naturalized in urban and rural areas, primarily used today as a large ornamental shade tree. Farmers introduced Northern Catalpa to Ohio in order to produce large amounts of relatively lightweight timber for fenceposts, since the wood is very resistant to rotting. Its rapid growth rate assisted in this need (along with other trees, like Black Locust and Osage-Orange) until metal fenceposts were developed and largely replaced wooden fenceposts. Also known as Hardy Catalpa, Western Catalpa, Cigar Tree, and Catawba-Tree, it may reach heights of 70 feet tall and 40 feet wide. As a member of the Bignonia Family, it is related to Trumpet Vine, Royal Paulownia, and other species of Catalpa, all of which are known for their showy flowers.

Planting Requirements - Northern Catalpa prefers moist, deep, rich soils of variable pH, but adapts to dry or wet soils, and soils that are poor or primarily clay. It withstands summer heat very well, and can be planted in zones 4 to 8.

Potential Problems - Although Northern Catalpa can have several diseases and pests, most are usually minor and pose no serious threat to this relatively trouble-free tree. The exception is the caterpillar of the Catalpa sphinx, which can on occasion defoliate the tree.

Three liabilities exist in urban areas where it is found as both a shade and an ornamental tree. Northern Catalpa rains down fragments of its long fruits and fringed seeds from winter through spring, creating a cleanup chore. In addition, it often gets far too big for its allocated space in the landscape, and crowds out or casts too much shade on other desirable plants. Finally, its brittle wood, coupled with tree height, makes its branches at times subject to wind or ice damage.

Leaf Identification Features

The medium-green leaves of Northern Catalpa are large, heart-shaped, and usually without any lobes. The leaves are also unusual in their arrangement around the stem, which is usually whorled (three leaves emerging around the same location along the stem) but sometimes opposite.

When the trees flower in early summer, the huge white flowers have a solid green background of foliage to contrast against.

Other Identification Features

The flowering structure of Northern Catalpa consists of a huge truss of individual flowers, each one of which has a corolla composed of fused white petals with small amounts of yellow, orange, and purple, upon close inspection.

Some of the perfect flowers quickly give rise to long, thin, pendulous fruiting structures that are green in summer, and persist as brown pods ("cigars") throughout much of the winter.

The winter twigs of Northern Catalpa are like those of few other trees, having sunken leaf scars that resemble suction cups. Their whorled arrangement (three scars per node) around the twigs is another give-away that this is a Catalpa tree.

The mature bark of Northern Catalpa varies from one tree to the next, with some being scaly, others ridged, and still others having the long ridges broken into rectangular blocky plates. The image shown also demonstrates that most large trees eventually fall victim to either high winds or, as in this case, a lightning strike.