Paulownia tomentosa (Thunb.) Sieb. & Zucc. ex Steud. (Family: Scrophulariaceae)
Princess tree is a showy, aggressive ornamental tree, usually 30-40 feet in height. It can reproduce both by seed and root sprouts. A single tree is capable of producing an estimated 20 million seeds that are easily transported long distances, and its root sprouts can grow more than 15 feet in one season. Fortunately, mature princess trees are often structurally unsound and rarely live more than 70 years.
Also known as: empress tree, royal paulownia, paulownia
Origin: Princess tree is native to western and central China where historical records describe its medicinal, ornamental, and timber uses as early as the third century B.C. It has been cultivated for centuries in Japan where it is valued in many traditions. It was imported to Europe in the 1830s by the Dutch East India Company and brought to North America a few years later. It has been naturalized in the eastern U.S. for more than 150 years and is also grown on the west coast.
Princess tree bark is rough, gray-brown, and interlaced with shiny, smooth areas. Its stems are olive-brown to dark brown, hairy, and flattened at the nodes. The smooth brown bark of young branches has prominent white lenticels.
Leaves are large, broadly oval, heart-shaped, or shallowly three-lobed. The lower leaf surfaces are noticeably hairy. They are arranged in pairs along the stems.
Princess tree flowers are conspicuous upright clusters of showy, pale violet, fragrant flowers that open in the spring.
Fruits are dry brown capsules that contain many tiny winged seeds. The capsules mature in autumn, opening to release the seeds, and then remain attached during the winter.
Distribution: Princess tree is found in 25 states in the eastern United States, from Maine to Texas. It grows rapidly in disturbed natural areas, including steep rocky slopes, previously burned areas, forests defoliated by pests, and scoured riparian zones. It can tolerate infertile and acidic soils and drought conditions. Recently it has also been grown in plantations and harvested for export to Japan where its wood is highly valued.
Problem: Princess tree can sprout prolifically from adventitious buds on stems and roots and survive fire, cutting, and even bulldozing in construction areas. It competes with rare plants in the marginal habitats where it thrives.
Control: Young princess tree seedlings may be pulled by hand when the soil is loose after a rain. The entire root must be removed since broken fragments may resprout. Mature trees can be cut at ground level when they have begun to flower to prevent seed production. Resprouts will be common after cutting, so cutting should be considered an initial control measure that will require re-cutting or herbicide treatment of sprouts. These may be controlled by applying a 2% solution of glyphosate or triclopyr plus a 0.5% non-ionic surfactant to thoroughly wet all leaves.
USE PESTICIDES WISELY: Always read the entire pesticide label carefully, follow all mixing and application instructions and wear all recommended personal protective gear and clothing. Contact your state department of agriculture for any additional pesticide use requirements, restrictions or recommendations.