The Empress Tree (Paulownia tomentosa), also sometimes called "Royal Paulownia" or "Princess Tree," is part of the shrubby Scrophulariaceae family, Native to China, it has long been used as an ornamental tree in the West and has naturalized itself in some places. Paulownia is fast growing and sometimes grows as much as 8 to 10 feet in a single year. The purplish flowers are the tree's chief glory. Clustered in panicles or flowerheads up to a foot long, the flowers bloom in the spring, making a great show. The medium green leaves are broad and shield-shaped or sometimes lobed and appear in opposed groupings on the trees. Paulownias are very decorative, but also have a few problems that make experts cautious about recommending them as landscape trees.
Because of its fast growing nature, the wood of the Empress tree tends to be brittle. This means that branches can be easily damaged by wind or rainstorms, making the trees less desirable for populated areas.
Paulownias put on a magnificent display of spring flowers, but the buds are extremely susceptible to freezing in the winter. Frozen buds die and affected trees produce no flowers the following spring.
The trees are relatively expensive to maintain in populated areas because they produce and abundance of "litter" that must be cleared away--dead flowers in the spring, leaves in the fall and the remnants of seed capsules at other times.
Ostensibly hardy to USDA Zone 6 (winter temperatures as low as -5 F.), the trees can die back to the ground in severe winters.