Basic info - Princess tree was introduced to the US as an ornamental and crop tree in 1840, and has since escaped from cultivation.
Impacts - The princess tree spreads aggressively, grows rapidly, and is very difficult to eradicate. Each fruit from this tree releases thousands of winged seeds which are carried by the wind to new locations. Once a seed becomes a juvenile tree, it can add 15 feet of new growth each year, reaching 50 feet tall in just 10 years. In this time, its dense canopy also reaches 30 feet in width, shading out native plants. Even after this tree is cut down, it can send up shoots from along its extensive root system, sometimes many feet from the original stump. These sprouts grow faster than new seedlings and make it extremely difficult to manage.
Identification - This plant is a deciduous tree that can reach upwards of 100 feet in height, although most specimens won't reach such a height. Princess tree leaves are quite large, usually around 6 to 12 inches long and 5 to 9 inches wide, but the leaves of younger plants have been observed to reach 3 feet long! This tree blooms in early spring with a spectacular display of large, purple, pleasant-smelling flowers, up to 2 inches long. The fruits that follow these blooms are somewhat small and egg-shaped, about 1 to 2 inches long and 1 inch wide. These fruits change from a light green in the summer to a dark brown in winter, at which time they then split open to release around 2,000 tiny seeds (~3 mm long) that are distributed by wind and water. This tree is most often confused for the Northern catalpa (Catalpa speciosa), which is a native tree.
What can you do to help? - If you've identified a princess tree, or think you might have but aren't sure, you can report your discovery on the EDDMapS (Early Detection and Distribution Mapping System) app or website or upload an image of it to the iNaturalist app.
Due to the princess tree's ability to regenerate from below ground roots, prescribed fire is not considered an option for management of this species. In fact, this ability means it will recolonize the area faster than native plants after a fire, actually increasing its populations.
Herbicide and manual removal such as cutting or pulling can be effective, but only if the site is monitored and retreated once or more per year. Also consider planting native species wherever a princess tree has been cut down to provide competition, hopefully slowing down its ability to re-sprout and recolonize the area. If you've chopped down a mature tree or pulled a seedling, ensure all plant parts are bagged and disposed of or burned. Never compost invasive plants!
In the case of such a prolific and hard to control species such as the princess tree, the best way to help can sometimes be electing not to plant it yourself, and spreading awareness to those around you about its impacts.
Some native alternatives to the princess tree include the Downy Serviceberry (Amelanchier arborea), Eastern redbud (Cercis canadensis), or Cucumber magnolia (Magnolia acuminata).
Written by: Clover McDougall
Banner photo by © Geolina, CC BY-SA 4.0, via Wikimedia Commons