The paulownia (Paulownia tomentosa), also called princess tree, royal empress tree or foxglove tree, is theoretically a fairly tall, fast-growing tree from 30 to 50 feet/10 to 15 m tall, usually grown for its abundant of pinkish-lavender trumpet-shaped flowers: sort of a jacaranda (Jacaranda mimosifolia) for moderate climates. Under the right circumstances, it quickly grows into a multi-branched, very presentable shade tree, although its tendency to self-sow over-abundantly has somewhat tarnished its reputation. (Note that there are sterile varieties—usually hybrids of P. tomentosa and P. fortunei—that can be used where self-sowing is a concern.)
Under normal circumstances, paulownias produce green 6 to 16 inch (5–40 cm) heart-shaped leaves that drop off without changing color in the fall. However, if the trunk is cut back to the ground (coppiced), it will resprout from the roots, producing thick, fuzzy branches 10 ft (3 m) or more in height. And the sprouts produce huge leaves: easily 2 feet (60 cm) in diameter, sometimes more!
Paulownias are also far more root hardy than stem hardy. Flower buds freeze at 0˚ F (-18’C) and the entire trunk can die at -10˚ F (-23˚ C) if the cold lasts more than a short time, meaning it can only be considered fully hardy in USDA zones 6b-11 (AgCan zones 7b to 11) and even then, not always in windier spots or at high elevations. However, they will readily sprout from the base as far north as USDA zone 3 (AgCan zone 4) and even colder as long as the roots are heavily mulched in the winter.
The result is just about anyone, even many Alaska gardeners, can grow paulownia … as a dieback shrub. No, it will never bloom when treated this way, but the giant leaves are very impressive and tropical looking.
This isn’t hard to do: just cut the branches to the ground in late fall or early spring and watch it grow taller than a human from essentially nothing each spring!
How long will it do this? I don’t know exactly, but the specimen grown in the Roger-Van den Hende Botanical Gardens in Quebec City has been coppiced annually for 40 years now and is still going strong! That ought to be sufficient for most gardeners.
Where to Find A Plant
Young paulownia trees are widely available in nurseries in mild climates … but almost never in colder ones. Nurseries seem to assume that, since it’s a zone 6b plant, gardeners in colder climates won’t want to grow it. Your best bet would be to grow on from seed … and the seeds sprout rapidly, easily and quickly. You’ll already have quite a presentable cutback shrubs the following year!
You’ll find dozens of sources of seed on the Web, including on eBay.