northern catalpa

not listed

N4? - Apparently Secure

SNA - Not applicable

not listed

FACU - Facultative upland

FACU - Facultative upland

FACU - Facultative upland

Northern catalpa is a medium-sized, moderately fast-growing, moderately short-lived, deciduous tree rising on a single trunk from a relatively shallow, spreading root system. It can be 50′ to 98′ tall and up to 48″ in diameter at breast height, though in Minnesota it is usually no more than 80′ in height and 24″ in diameter.

The trunk is relatively stout and usually somewhat crooked but may be straight. The crown is irregular.

The bark on mature trees is reddish-brown, rough, and divided into shallow, irregular furrows and vertical ridges with thick scaly plates.

Young twigs are stout, green, and hairless with scattered white dots (lenticels). Older twigs are reddish-brown. The pith is continuous. The leaf scars are round or shield-shaped and distinctly raised but depressed in the center like a suction cup. They have numerous bundle scars forming an oval.

There are no terminal buds. Lateral buds are small and are covered with dark brown to black scales.

The leaves are deciduous and are arranged in whorls of three. They hang downward on 1½″ to 5″ long, light green, hairless or mostly hairless leaf stalks (petioles). There are no leaf-like appendages (stipules) at the base of the petiole. The leaf blades are heart-shaped, unlobed, pinnately veined, 5½″ to 8¼″ long, and 4½″ to 6¾″ wide. They taper to a long point at the tip with concave sides along the tip. The upper surface is dull, green, and hairless. The lower surface is pale and densely covered with short curly hairs, especially along the veins. The margins are untoothed. In autumn the leaves turn pale yellowish-green and fall before turning yellowish-brown.

The flowers are bisexual, having both male and female parts. They appear when the leaves are fully grown in May to June. The inflorescence is large, showy, 5″ to 10″ long and wide, branched cluster (panicle) of 10 to 30 flowers at the tips of branches.

Individual flowers are more or less bell shaped, 2″ to 2½″ long, 1½″ to 2″ wide, and bilaterally symmetrical. There are 5 sepals, 5 petals, 2 fertile stamens, 3 infertile staminodes, and 1 style. The sepals (calyx) are fused together into a ⅜″ to ½″ long tube. The calyx is hairless and tinged with purple. It splits open deeply at maturity into 2 irregular lobes. The petals are fused at the base into a tube about 1⅜″ long, then separated into 5 unequal lobes. The lowest lobe is shallowly notched. The petals are bright white with two yellow to orange patches and several brownish-purple dots and lines at the throat. The staminodes are short. The stamens are long but do not protrude from the corolla tube. The style is white with a 2-lobed stigma. The flowers are fragrant but inhaling their aroma may be poisonous to some individuals.

The fruit is an 8″ to 16″ long, ⅜″ to ⅝″ in diameter, bean-like seedpod containing numerous seeds. The seedpod is narrowly cylindrical, round in cross section, and relatively thick-walled. It is light green at first, turning brown at maturity. The seeds are flat, light brown, 5 ⁄16″ to ⅝″ long, and ⅛″ to ¼″ wide. They have a papery wing and a tuft of long hairs at each end. After the seeds are released the sides of the seedpod (valves) remain concave. The seedpod ripens in the fall and remains on the tree, opening slowly and releasing seeds throughout the winter and spring.

50″ to 80″

No record for non-native trees

White with yellow and purple markings

Moist but well-drained. Alluvial forests in south-central US. Full or partial sun.

May to June

Catalpa sphinx (Ceratomia catalpae) caterpillars can defoliate the tree.

In the 1930s and 1940s northern catalpa was widely planted as a windbreak and cultivated for fence posts in Ohio. It is still sold and planted as a shade tree and ornamental because of its large leaves and showy flowers.

Sources

2, 3, 4, 7, 22, 24, 29, 30.

The map at left includes observations listed on iNaturalist.org. Some of those sightings are in people’s yards.

Native to Missouri, Arkansas, Illinois, Indiana, Kentucky, Tennessee, and Texas. Introduced and cultivated farther north and west. Widely spreading.

Adventive and locally naturalized in Minnesota.

Prior to European settlement the range of northern catalpa had contracted to a small area around the confluence of the Mississippi and Ohio Rivers. It has now become naturalized from Kansas to Virginia north to southern Michigan and southern Wisconsin. Its range continues to spread and now includes almost all states east of the Rocky Mountains. In Minnesota it is not fully established but is locally naturalized. It is hardy up to zone 4, which includes the southern half of the state.

sapling growing by my back door.

Northern Catalpa. Freeborn County, MN, June 2017

Northern Catalpa in Owatonna, MN

Habitat

Mature tree

Young tree

Leaf

Flowering branch

Inflorescence

Flower

Twig

Infructescence

Fruit

Location: Indiana

sapling growing by my back door.

Location: Golden Valley, MN - Hennepin County

Location: Freeborn County, MN

Location: Owatonna, MN