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Owen Johnson (2022)
Johnson, O. (2022), 'Paulownia elongata' from the website Trees and Shrubs Online (treesandshrubsonline.
A tree of exceptional vigour in warm-temperate conditions. Leaves cordate, almost as broad as long, with dense stellate hairs underneath, glabrescent above. Flowerhead c. 30 cm long; cymes with peduncles almost as long as the pedicels. Calyx lobed to a third of its length, glabrescent. Corolla bell-shaped, 70–95 × 40–50 mm (at the mouth), pinkish-white to purple, spotted purple; lower lip strongly ridged. Fruit capsule ovoid, 35–50 mm long, with stellate hairs; wall to 3 mm thick, not woody. (Hong et al. 1998).
Distribution China In the south of the country; cultivation has masked the original wild distribution.
Habitat A pioneer species.
USDA Hardiness Zone 7
RHS Hardiness Rating H5
Conservation status Not evaluated (NE)
The exceptional vigour of Paulownia elongata has made it a favourite with foresters, though as a flowering plant there is little to choose between this and the other members of this close-knit genus; its southerly origins means that a long, warm growing season is needed for the tree to perform at its best.
The first plantation to be established outside China may have been in Polk County, North Carolina, where an experimental 1.3 ha plot was established by 1979 (Hall 2008). By the 1980s, the species’ potential drought-tolerance had attracted the interest of South African foresters (Donald 1990), and Paulownia elongata also seems to have been at the centre of attempts to establish a timber industry in New Zealand, promoted by the Paulownia Action Group from 1989 (Laurence 2007). Many of these New Zealand plantations failed, but one successful contemporary use of P. elongata is Graham and Tess Smith’s at South Waikoto in the central North Island (Dean 2022).
The species’ use as a garden tree has been much more limited. The oldest examples are perhaps two planted in 1992 at the Westonbirt National Arboretum in the UK, which have grown happily though unspectacularly and were 16 m × 34 cm dbh and 11 m × 30 cm dbh in 2014; a 2005 accession at the Sir Harold Hillier Gardens was just 7 m × 11 cm in 2021 (Tree Register 2022). The original 2004 planting at the UK National Collection near Bath was one of David Ewins’ very few failures, and was replaced in 2017 (D. Ewins pers. comm. 2022). Paulownia elongata remains available from a few specialist nurseries in the UK, Ireland, the Netherlands and Australia, and has succeeded at the C. R. Keith Arboretum in North Carolina (Hatch 2021–2022).
As is the case with several other rarer Paulownia taxa, there is scant documentation to confirm the origins (and genuineness) of today’s plantings. Conversely, it needs to be emphasised that there is remarkably little to choose between the species in terms of ornamental interest, and that others seem more reliably adapted to northern Europe’s cool and uncertain summers.
An extra-vigorous selection offered in the United States by paulowniatree.com in 2003 (Hatch 2021–2022); perhaps derived from the 1979 plantation in Polk County, North Carolina.
Synonyms / alternative names
Paulownia elongata COTEVISA 1®
‘PWCOT-1’ was one of nine forestry clones trialled at Hillsborough in Northern Ireland early in the 21st century; it was supplied from Spain and stated to be a clone of P. elongata (Olave et al. 2015). What is presumably the same clone is now commercially available for forestry use as COTEVISA 1® (Royal Horticultural Society 2022).