Family: Paulowniaceae

Origin, Description & Uses
Paulownia tomentosa (princess tree) is native to Central and Eastern China and South Korea. It is a very fast-growing deciduous tree known for its large, heart-shaped leaves and showy, fragrant lavender flowers that appear in spring before the foliage. Because of its rapid growth and ability to reach moderate to large size quickly, it is widely planted as an ornamental shade tree in parks and gardens. It has also been promoted in some regions for timber production, biomass, and soil stabilization due to its light, fast-growing wood and tolerance of disturbed sites.

Risks & Threats
In Hawaiʻi, Paulownia tomentosa is naturalized and has demonstrated traits that are cause for concern, including extremely high seed production, wind-dispersed seeds, and the ability to establish quickly in disturbed areas. These characteristics allow it to spread beyond plantings and potentially compete with native vegetation, particularly in open or disturbed tropical island ecosystems where native regeneration may be impacted. It can alter habitat structure and reduce biodiversity by forming dense stands that shade out slower-growing native species. Because of these risks, it could detrimentally impact tropical island ecosystems if it continues to spread. When available, choosing a low-risk or native alternative is recommended for landscaping and restoration projects.

High Risk Traits:

• Naturalized beyond native range (Hawai'i, eastern U.S.)
  
• Considered a weed in the U.S. (disturbed areas, roadsides, gardens)
  
• Environmental weed (competes with rare plants in marginal habitats)
  
• Tolerates a wide range of soil conditions (sandy, loam, clay, infertile, acid)
  
• Reproduces by root sprouts (vegetative fragmentation)
  
• Prolific seed production (up to ~20 million seeds per tree)
  
• Wind- and water-dispersed seeds
  
• Persistent seed bank (>1 year)
  
• Tolerates mutilation, coppicing, and fire (resprouts from roots/stems)

Low Risk Traits:

• No spines, thorns, or burrs
  
• Palatable to grazing animals (good fodder)
  
• Not toxic to animals
  
• No evidence of human allergies or toxicity
  
• Unlikely to create fire hazard
  
• Not shade tolerant (requires full sun)
  
• Requires 8–10 years to flower
  
• Propagules not adapted for attachment (unlikely to disperse unintentionally)
  
• Well controlled by herbicides