How to Manage and Maintain Paulownia tomentosa

Royal Paulownia purple blossoms hanging from a tree with green leaves.

candiru / Flickr / CC PDM 1.0

Royal Paulownia is a native of China where it is revered as a tree and loved for both its legends and its usability. The tree's form is a bit ragged but can provide an enjoyable and dramatic, coarse-textured appearance with huge heart-shaped leaves and large clusters of lavender flowers in the spring. Paulownia flowers are usually set before leaf emergence so they really stand out against a neutral or evergreen background. With its rapid growth rate, the princess-tree can reach 50 feet in height with an equal spread in an open landscape.

Royal Paulownia Specifics

Paulownia tomentosa blossoms on branches against a blue sky.

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  • Scientific name: Paulownia tomentosa
  • Pronunciation: pah-LOE-nee-uh toe-men-TOE-suh
  • Common name(s): Princess-Tree, Empress-Tree, Paulownia
  • Family: Scrophulariaceae
  • USDA hardiness zones: 5B through 9
  • Origin: not native to North America
  • Uses: reclamation plant; tree has been successfully grown in urban areas where air pollution, poor drainage, compacted soil, and/or drought are common
  • Availability: grown in small quantities by a small number of nurseries

Invasive Exotic Status

Seed pods of a Paulownia tomentosa against a blue sky.

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Royal paulownia is a prolific seeder but not welcomed by many forest owners. Woody seed capsules form in autumn containing up to two-thousand seeds and can cover a large area using wind power. The seeds persist through the winter and have a high germination percentage. Seeds germinate readily in the landscape and because of this ability to take over a site, paulownia has been given invasive exotic tree status and planters are cautioned about its reproductive potential.

Royal Paulownia Description

Empress tree in bloom against other trees.

James Gaither / Flickr / CC BY-NC-ND 2.0

  • Height: 40 to 50 feet
  • Spread: 40 to 50 feet
  • Crown uniformity: irregular outline or silhouette
  • Crown shape: round; vase shape
  • Crown density: moderate
  • Growth rate: fast
  • Texture: coarse

Trunk and Branch Structure

Detail shot of a Paulownia tomentosa's bark.

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Royal paulownia's bark is thin and easily damaged from mechanical impact so be careful using equipment around the tree. Paulownia has a characteristic droop as the tree grows and will require pruning for vehicular or pedestrian clearance beneath its canopy. The tree is not particularly showy and to improve its appearance, it should be grown with a single leader. There is a major pruning requirement: the tree needs regular pruning to develop a strong structure.

Paulownia Foliage

Close up of Paulownia tomentosa leaves and seeds.

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  • Leaf arrangement: opposite/subopposite
  • Leaf type: simple
  • Leaf margin: entire
  • Leaf shape: cordate; ovate
  • Leaf venation: pinnate; palmate
  • Leaf type and persistence: deciduous
  • Leaf blade length: 8 to 12 inches; 4 to 8 inches
  • Leaf color: green
  • Fall color: no fall color change
  • Fall characteristic: not showy
  • Pruning a Royal Paulownia:

The "Princess-Tree" expresses rapid growth and can reach 8 feet in two years from seed. This causes frequent winter kill to tender growth. You will not find this to be a problem if you prune down to where an axillary bud can take over as the single leader. It is important to build a single leader as long as possible and there should be a clear stem to the first main branch at 6 feet or higher. This pruning process is especially important if you are wanting to utilize the tree for its wood.

Royal Paulownia In-Depth

Blooms and leaves on a Paulownia tomentosa.

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Paulownia thrives best in deep, moist but well-drained soil that is sheltered from the wind. The tree has become naturalized in many parts of the southern United States so you can see them most anywhere in lower North American latitudes. Fuzzy, brown flower buds form in early autumn, persist over the winter and bloom in early spring. These buds may freeze in very cold weather and drop off.

Woody seed capsules form in autumn containing up to two-thousand seeds. They can easily hibernate through the winter and germinate readily in the landscape or wherever they are carried. Leaves rapidly drop within one week following the first frost in autumn.

Storm damage can be a problem as the tree is susceptible to breakage either at the crotch due to poor collar formation or the wood itself is weak and tends to break. It has no known insect enemies. There have been occasional reports of problems with mildew, leaf- spot and twig canker.