The empress tree (Paulownia tomentosa) grows to a height of 50 feet with a 30- to 40-foot width. In May, prior to foliage emerging, the tree produces large, striking clusters of purple, tubular shaped flowers. Once flowers appear, the foliage starts to grow. The leaves measure 2 feet long. Brown, fuzzy flower buds are produced in the fall and spend the winter on the tree before blossoming in the spring. Seed capsules also form in the fall beside the flower buds.
In the 1840s the empress tree, also called the "princess tree," was introduced to the United States, where it quickly became a popular ornamental. The tree quickly naturalized throughout the Eastern states and along the Western coast. The tree is widely grown on tree plantations for its wood production. The tree is considered to be quite invasive in many states.
The empress tree grows along roadsides, stream-beds and throughout forests. The tree tolerates a wide range of soils that are both alkaline or acidic. It can also withstand drought once established. The tree will regenerate and spread from its root system, which gives it the ability to survive forest fires. It tolerates partial shade but prefers full sunlight for maximum growth.
One tree produces over 20 million seeds, according to the U.S. National Park Service. Seeds form in capsules that contain four compartments. Each compartment contains several thousand seeds that bear wings for wind transportation and spread. Seed capsules open in the fall.
Seeds germinate shortly after distribution. Seedlings grow vigorously. When the tree reaches 8 to 10 years of age, it begins to produce seeds. The empress normally lives to be 70 years old and then begins to become structurally unsound. Growth is drastically reduced, and the tree becomes susceptible to disease and breakage.
The empress tree produces a large, spreading root system. The tree easily reproduces from root sprouts. Root sprouts grow vigorously and often attain a height of 15 feet in a single season.
The wood of the empress tree is extremely valuable and often exported to Japan, where the lightweight wood is fashioned into jewelry boxes and furniture. Currently, the wood is considered one of the highest priced saw-timbers in the world, according to the U.S. Forest Service.