The Paulownia tomentosa tree, also known as the princess tree, royal Paulownia or empress tree, is a deciduous tree that is often grow as an ornamental. The tree originates from western and central China and was introduced to the United States as a landscape tree in the 1800's. It has since become wild in much of the Eastern United States and in some areas on the West Coast. Now, it has spread so prolifically that it is considered an invasive species.
The leaves of the Paulownia tomentosa tree are large and heart-shaped, sometimes have three shallow lobes, and slightly frilled margins. They are smooth on the top surface, with hairy undersides. The leaves are attached to long stems that grow in alternate pairs along the branches of the tree. The tree also produces flowers that growing in large, showy clusters. The flowers are somewhat bell-shaped, pale by living color, and are fragrant. The seed pod of the plant resembles a pecan and will split open in the fall to release thousands of tiny winged seeds that are dispersed by the wind.
Paulownia tomentosa can often be found growing along forest edges, stream banks and roadsides. It can even grow on rocky outcroppings. The plant will often infiltrate areas that are recently defoliated for reasons such as fires, pests, landslides or other natural occurrences. This can often displace more slow-growing native species.
The tree can grow to 60 feet tall and can have a trunk up to 2 feet in diameter. Paulownia tomentosa grows extremely fast and can put on as much as 15 feet of growth in a single season. It grows well in hardiness zones 7 through 11 and tolerates a wide range of soils, including those that are considered less fertile or acid. It requires little water and handles drought conditions easily.
The princess tree is still grown in many areas as an ornamental; however, increased concern over its invasive behavior has discouraged its use within landscapes. In recent years, the tree has been cultivated for its wood, which is highly prized in foreign markets. The wood has a silky feel and light golden color. It takes stains well and is easy to work.
There are three primary means of control of the species. Chemical controls in the form of herbicides, such as Roundup and Garlon, can be used on tree seedlings and small trees. Care should be taken when using foliar sprays. Girdling may be more effective for a larger trees. This is accomplished by using a hatchet to cut through the bark completely around the base of the tree. This prevents the tree from taking up water and nutrients from the soil, eventually killing it. Cut stump application involves cutting seedlings, saplings and older trees off just above the crown of the plant. A solution of Roundup or Garlon is painted onto the fresh cut to kill the tree and prevent re-emergence.