Catalpa trees have been used widely in urban landscaping for their beautiful and dramatic flowers and spring foliage. Although they are native to the United States, they are not native to the Carolinas. There are two species of Catalpas found in North Carolina. Catalpa bignonioides is the Southern Catalpa, whose original native range is a small area of the Southeast, centered primarily in southern Mississippi and Alabama. The Northern Catalpa, Catalpa speciosa, originated in a small, narrow territory in the Midwest near the junction of the Ohio and Mississippi Rivers. Both species occur in North Carolina as either escapes from cultivation or as planted trees. They are distinguished from each other only by minor differences in the flower and fruit.; the leaves are nearly identical.
Below is a photo of a young Catalpa tree in an open field in the Falls Lake Area.
A typical leaf from that tree.
Paulownia trees originated in China and are both exotic and invasive in North America. Paulownia tomentosa is also called Princess Tree or Empress Tree and is a very rapid grower. Unfortunately it greatly outnumbers Catalpas in the Falls Lake area.
Below is a young Paulownia tree from an erosion control area near Falls Lake.
Due to their huge leaf size and similar flowers, Catalpa and Paulownia trees are often confused with each other. There are a few simple ways to easily tell them apart. For example, Catalpa flowers are white; Paulownia flowers are described as lavender, purple or violet. Here are a few more easy field identification pointers:
Catalpa leaves occur in whorls of three. See below.
Paulownia leaves are opposite, always in pairs.
The Paulownia leaf is usually much larger and broader than the Catalpa leaf. Below is an average sized Paulownia leaf on the left, with a very large Catalpa leaf on the right.
The fruits (pods) of the two trees are very different. The Catalpa tree has long, narrow pods that give rise to the common name Indian Cigar or Indian Bean. The Catalpa pods shown below are about 18 inches long and come from a large tree near the Falls Lake Dam. The Paulownia tree has rounded, woody seed capsules that taper somewhat at the tip. Both trees retain their fruit well into mid or late summer, aiding identification of the larger, mature trees.
In spite of similar appearances, the two trees are not related, but lie in separate plant families. Catalpas are in the family Bignoniaceae , and Paulownias are in the family Paulowniaceae.
1. Catalpas are scarce; Paulownias are common.
2. Catalpa leaves are large, but Paulownia leaves are larger, often much larger.
3. Catalpas have leaves in whorls of three; Paulownias have two opposite leaves.
4. Catalpa flowers are white; Paulownia flowers are lavender to purple.
5. Catalpa fruit is a long, narrow pod; Paulownia fruit is a rounded, woody capsule.