This section is from the book "Commercial Gardening Vol4", by John Weathers (the Editor). Also available from Amazon: Commercial Gardening, A Practical & Scientific Treatise For Market Gardeners.
A fine deciduous Japanese tree, 40 ft. or more high, with large heart-shaped leaves and clusters of purple-violet Foxglovelike flowers spotted inside with purple brown, rarely seen in Britain. It is chiefly used for subtropical effect in summer by inducing stout stems to spring up as the result of severe pruning. The Paulownia grows in any good garden soil, and is increased from seeds, cuttings of the ripened wood, and also by root cuttings.