The empress tree, Paulownia tomentosa, also called royal Paulownia or princess tree, is an extremely fast growing tree, often growing 6 feet a year to a height of 40 or 50 feet. Because it grows so quickly and seeds prolifically in mild winter areas, it is often considered to be a weed tree, though it can also be a valued shade tree in the right situation.
The empress tree has large (1 foot or more in length) heart-shaped leaves that look a bit like those of the catalpa. Its 40-foot height is equaled by the spread of its nearly horizontal branches. The trunk is wide and substantial.
In early spring, 2-inch-long, fragrant, funnel-shaped lilac flowers bloom in upright, 1-foot-high clusters. These look somewhat like foxglove flowers, and the inside is striped with yellow and spotted with darker lilac. They are followed by 2-inch, top-shaped seed capsules.
The empress tree is native to China, Japan and other areas of eastern Asia, though it has been harvested almost to extinction in Japan. The light wood has long been used for musical instruments, furniture, carvings and bowls. It was once a tradition in China to plant an empress tree when a baby girl was born and make a dresser out of the wood when she married.
Paulownia thrives in many soils, even under drought conditions, but does best in deep, rich, moist ground. It seems to take poor or polluted soils quite well, and is used in China for land reclamation. Give it full sun.
Because the of its quick growth, the wood is rather weak, so plant it where it will be protected from strong winds.
It is hardy to USDA zone 5, though in the coldest areas the buds will freeze, reducing the show of flowers. It may also drop buds in very mild areas.
With its big leaves and showy flowers, Paulownia gives a tropical appearance to cold winter gardens. Some people cut it back to a few feet every year to enhance the tropical effect by forcing out 6- to 8-foot sprouts with elephant-ear sized leaves. This, unfortunately, almost eliminates flowers.
As a shade tree, it is valued for the showy flowers and quick growth. It can be kept lower than 30 feet with pruning, but you'd be better off giving it the root it needs.
If you're landscaping a new home, you may wish to plant an Empress tree for its quick growth and fast shade potential and, if you wish, you can remove it as smaller, slower growing trees mature.
The empress tree produces masses of fluffy seeds and has naturalized in mild winter areas of the east coast of the U.S. The seeds germinate so easily--sometimes even sprouting on rooftops--that they colonize open areas quite easily, becoming a nuisance.
The falling leaves and flowers may be a problem if the tree is planted over sidewalks or patios. Look for a place where the litter can be raked up occasionally without becoming a slippery mess. The mature trees cast deep shade and have dense surface roots, making them difficult to garden beneath.
If you wish to remove a Paulownia from your yard, you can cut it down and then remove all the sprouts that spring up so quickly from the trunk. Eventually it will exhaust its energy and stop sending up shoots.
You may also paint the stump with a brush killer that is translocated to the roots, killing them and eliminating sprouts.