I have come across the Paulownia or Princess tree often lately, and its features beg for my attention. It appears out of place in the Atlanta area landscape, an invasive exotic that some debate is not truly invasive. Though it is an introduced ornamental, I have never noticed it purposely used in a landscape. Its large tropical-looking leaves draw attention in odd places such as by train tracks or road overpasses, on hillsides or by a dumpster. As you read further about this tree’s history, uses and features, you are sure to discover that you, too have encountered this tree and you will enjoy learning about it.
The Paulownia or Princess tree (Paulownia tomento
sa) is known by several other names: Royal Paulownia tree, Chinese Empress tree, Kiri tree. The genus was reportedly named in honor of Queen Anna Pavlona of the Netherlands (1795-1865) by Tsar Paul I of Russia, to copy a Japanese tradition. The species name tomentosa refers to the hairy underside of the tree’s large leaves. The common name Kiri (to cut) was given referring to the belief that the tree would grow better and quicker when it was cut down.
The Paulownia tree is native to western and central China where historical records describe its uses as early as the third century B.C. It has a long history of cultivation throug
hout the Orient, and it is valued in many traditions. In more than one country it has been customary to plant a Paulownia tree when a daughter was born, and then make it into a dresser or hope chest as a wedding present when she married. It was brought to France from Japan by a Dutch physician in the 1830s, and it was brought to a New York nursery in the 1840’s. Fossil records in the state of Washington show that the Paulownia tree grew in North America before the later ice age. Since this re-introduction to North America, Paulownia has become naturalized in at least 33 states, to mixed reviews. It is considered both an invasive trash tree to be eradicated and an extremely valuable tree to be cultivated (primarily for export to Japan). Though 
Paulownia wood is very much valued in the Orient, demand in North America is not yet developed.
In Japan, Paulownia wood is valued for its many good qualities. The attractive whitish colored wood is nearly as light as balsa but twice as strong. It is straight and fine grained with a silky feel. It is warp resistant, has good resonance qualities, resists insects and decay, and is a very good insulator with twice the R factor of pine or oak logs. Being an insulator with temperature resistance, it exhibits high fire resistance requiring a temperature of 800 degrees F for ignition which is almost twice that for typic
al hardwoods. The wood is easily worked and will not split or crack when spikes are driven into it or with rapid drying. The wood is burned to make charcoal for sketching and powder for fireworks. The bark is used to make a dye, and the leaves are an ingredient in vermicide preparations (to kill intestinal worms). In not only Japan but China and Korea the wood is used for making the soundboards of stringed musical instruments. In World War II the wood was used in the Japanese Zero aircraft because of its light weight and great strength.
The Paulownia tree belongs to the Figwort family, 
which is otherwise made up of herbaceous species. Though classified as a hardwood, the tree starts its life growing quickly as a reed with a soft white sponge-like center. As the tree matures, this center turns woody but remains soft or becomes hollow. A tree can grow 10 feet in the first year and twice that if the tree is cut down to sprout back up. The Paulownia tree is known for this extremely fast growth, and a tree may grow to 65 feet or more.
The Paulownia tree is most often found growing in disturbed soil and is easy to identify by its flowers, leaves and seed pods. The tree produces terminal 6 to 12 inch long upright panicles or clusters of purple flowers in April or May. They emerge from round, 
brown and hairy buds that were formed the previous summer. These flowers are tubular and have both male and female parts. The flowers are showy and fragrant, but are soon hidden by broadly ovate heart-shaped leaves which appear opposite on long stems. These elephant ear-like leaves taper to a point with smooth or shallowly lobed edges. The leaves are dull light green on top and paler green and tomentose underneath. Adult tree leaves are 6 to 16 inches long and 4 to 8 inches wide, but leaves may be twice as large on stump sprouts. Leaves turn brown and drop early, in September or October. Large clusters of sticky green pecan-shaped seed pods become 
brown and woody and remain on the tree past winter, as the above picture shows. Each seed pod is about 1.5 inches long and has 4 compartments. The base of each pod has a 5-lobed calyx. Each pod releases about 2000 tiny winged seeds, and one tree may produce 20 million seeds. These seeds (thankfully) are susceptible to damping-off disease caused by a variety of soil fungi, so only those seeds falling on disturbed bare, moist sterile soil successfully produce seedlings. These seedlings are further limited by being intolerant of shade and competing vegetation. Another way Paulownia propagates is from root cuttings, when 
roots of trees are disturbed. Paulownia trees are often planted for strip mine soil reclamation.
The rest of the Paulownia tree is also interesting. The bark of the Paulownia tree is gray-brown and rough, with interlaced smooth areas. Young branches have smooth brown bark with prominent white lenticels. These lenticels are raised spongy areas in the bark to allow for the exchange of gasses between the internal and external areas. Twigs are stout and brittle, with a hollowed or chambered center. The Paulownia tree does not produce a true terminal bud to continue straight upward growth year to year. Instead, lateral side buds develop int
o a new leader, and this produces a stem crook. Commercially grown young trees are most often cut down to the ground before spring growth in a process called coppicing. The stump that is left produces multiple new sprouts that are thinned, and the single sprout that is left grows twice as fast producing a longer section of straight trunk. Though coppicing produces more timber faster for market, naturally growing trees bring the highes
t price on the market because the more slow-growing wood is more durable and its pale light wood has interesting patterns. Many have invested in this fastest growing hardwood tree in the world, to take advantage of its high demand in Japan. However, the market for Paulownia wood there is unsteady- especially for the poorer grade trees that are now being obtained more cheaply from sources closer to Japan. Given the quality of the wood and how the tree grows to timber quicker than native trees, the Paulownia tree is sure to be an important source of timber in America’s future.
When you next come across a tree with large heart-shaped, tr
opical-looking leaves, you should be able to identify it. Only the Catalpa tree comes close in appearance, and it is easy to separate the two with the information given. This is an interesting tree to know.
The following ad illustrates use of Paulownia wood in oriental musical instruments. This instrument is a guqin, in the zither family. This and similar items are available for purchase here through my participation in the Amazon Services LLC Associates Program. Any purchase through this link helps maintain this website and is appreciated.