Paulownia tomentosa aka Paulownia

Paulownia tomentosa has two names: princess tree and empress tree. It belongs to the Paulowniaceae family and sheds its leaves. It comes from central and eastern China and southern Korea. It grows fast and forms a broad, rounded crown. Garden trees reach 30–50 feet (9–15 metres) tall. Reports give a spread of 20–50 feet (6–15 metres). Some trees reach 60 feet (18 metres) in height. Its dense shade can limit plants that grow beneath it.

Its thin, grey-brown bark has shallow cracks and small pores called lenticels. The thick brown twigs have many of these pores too. The large leaves grow in pairs, each opposite the other. Each simple leaf has one blade, not separate leaflets. Leaves are oval or heart-shaped, and some have shallow lobes. Soft hairs cover both sides; the underside is paler green. The leaves give the tree a coarse, bold outline. They fall in autumn without a strong show of colour. Fallen leaves and fruit can cause a litter problem.

The flowers smell sweet and range from pale violet to pink. They open before the leaves, in April or May. Sources give these months, with the time varying by place. Upright flower clusters, called panicles, hold blooms shaped like funnels. The blooms have spots and yellow stripes. Their scent is like vanilla; their shape is like foxgloves. Flowers grow on wood formed in the year before. Brown, woody seed cases, called capsules, follow the flowers. They can stay on the tree through winter. Each holds thousands of small seeds with wings. The cases split and let out these seeds in autumn.

The tree grows best in full sun but accepts some shade. It prefers deep, moist, rich soil that drains well. It copes with clay, loam, sand, and varied soil pH. It also copes with some drought and polluted city air. Sources give USDA zones 5–9, but cold can harm flower buds. The RHS gives it H5 and advises shielding young trees from frost. A sheltered site helps keep wind from harming its weak wood. Cutting it near ground level leads to large leaves. This also stops the tree from flowering.

People grow this tree for its flowers, shade, and timber. Makers use its wood for furniture, paper, carvings, and musical instruments. The flowers are edible and can serve as salad garnishes. The evidence does not make clear whether other parts are toxic. Pests seldom cause serious harm, but some diseases can occur. These include mildew, leaf spot, twig canker, and honey fungus. Seeds spread freely, and cut trees send up root shoots. Several US sources call it invasive and advise against planting it.