Description
Paulownia tomentosa is a medium to large deciduous tree, growing up to 20 m tall, with a broad, often rounded crown. Leaves are opposite or sometimes whorled in threes, cordate (heart-shaped), hairy above and below. The leaf blade is up to 40 cm long, and margins are entire or with 3 to 5 shallow lobes; young leaves may have toothed or wavy margins. The bark is grayish brown, smooth with lenticels when young, becoming furrowed with age. Flowers are borne in large, many-branched clusters from April to May; each branch has 3 or 4 flowers on pedicels about 1 to 2 cm long. The calyx is bell-shaped, fuzzy on the outside surface. The corolla is funnel- or bell-shaped, 5 to 7.5 cm long, purple, glandular on the outer surface; the upper lip is divided into two lobes and the lower lip divided into three. Flowers have four stamens each that are up to 2.5 cm long; the ovary is ovoid. From August to September, the ovary matures to become a woody capsule that is ovoid, 3 to 4.5 cm long, covered with sticky glandular hairs, splitting open to release the tiny seeds that are 2.5 to 4 mm long and winged (Wu et al. 1998).
Paulownia tomentosa is similar to other species of Paulownia in its range, but the inflorescences are pyramidal in shape, the fruit is egg-shaped with a pointed beak, and the capsule is glandular-hairy (Wu et al. 1998). Additionally the leaves are similar to those of Catalpa species, but in Catalpa the flowers are not purple and the fruits are long, hanging, and cigar-shaped (Del Tredici 2010).
Two varieties are known: the main variety tomentosa has leaves with heart-shaped bases that are densely hairy on the lower side, while variety tsinlingensis tends to have leaves with more rounded bases that are sparsely hairy on the lower side (Wu et al. 1998).
Uses
Note: Please see the disclaimer regarding any information about medical or edible uses.
Paulownia tomentosa is a hardy ornamental and is often grown in temperate areas. It prefers well-drained, medium-moisture soils in full sun, and grows in USDA zones 5 to 8 (MBG). The wood of Paulownia tomentosa is light and fine-grained, and is valued in Japan for specialty products, particularly dowry chests (Snow 2014). The seeds were once used as packing material for Chinese porcelain, and the discarded seeds reportedly contributed to its spread in the eastern United States (Del Tredici 2010). The flowers are edible (MBG). Parts of the tree including the bark and leaves were used in concoctions to treat a variety of ailments (Snow 2014).
Distribution
Paulownia tomentosa grows at altitudes below 1800 m. It is native to China, from the provinces of southern Liaoning west to northern Sichuan, east to Jiangxi and Jiangsu. Variety tsinlingensis is found between northern Sichuan and Shandong provinces (Wu et al. 1998); sources disagree on whether it is native or introduced to South Korea (Wu et al. 1998; Hassler 2022). It is cultivated and naturalized in Taiwan, Japan, Central Europe, Central and South Asia, the United States from Massachusetts and Texas, and New Zealand (Hassler 2022). Although often cultivated for both ornament and in plantations for its wood, it is also quite invasive, especially in North America. One tree can produce millions of seeds per year and regrow when cut, a characteristic that has given it a mythical, “phoenix-like” reputation in Asia, but led to its reputation as weedy in North America (Snow 2014).
Status
References
Hassler, M. 2022. World Plants. Synonymic Checklist and Distribution of the World Flora. Version 14.0; last update 2022 August 2. [accessed 2022 Aug 17]. <a>www.worldplants.de</a><br><br>Del Tredici, P. 2010. <i>Wild Urban Plants of the Northeast: A Field Guide</i>. Ithaca, NY: Cornell University Press.<br><br>MBG (Missouri Botanical Garden), Paulownia tomentosa. <i>Plant Finder</i>. [accessed 2022 Aug 17]. <a>https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=a888</a><br><br>Snow, W. A. 2014. Ornamental, crop, or invasive? the history of the Empress tree (<i>Paulownia</i>) in the USA. <i>Forests, Trees and Livelihoods</i>, 24: 85–96.<br><br>Wu, Z. Y., Raven, P. H., and Hong, D. Y., eds. 1998. <i>Flora of China. Vol. 18 (Scrophulariaceae through Gesneriaceae)</i>. Beijing: Science Press, and St. Louis: Missouri Botanical Garden Press.
