This hybrid is a cross between the American eastern and black cottonwoods (P. deltoides × P. trichocarpa). The first to cross the two species was the botanist A. Henry in 1914, with the aim of developing fast growing cottonwoods for the forestry industry, though the resulting cross has also been used as a park tree.
Both male and female clones have been taken into production. The females have been much more favoured in Finland, since their female catkins look like long strings of pearls. However, the specimen at Mustila is a male clone, which doesn’t produce the “woolly” seeds of the female to spread with the wind.
The hybrid has a rather sparse crown. The lead shoot is strong-growing, thick and angular. Few root suckers are produced. The leaf stalk is characteristically round and very long, up to 8 cm, and the leaf large, 9 x 8cm. Together these features make the leaves flutter in the slightest breeze.