Kindly sponsored by a member of the International Dendrology Society.
John Grimshaw (2016)
Grimshaw, J. (2016), 'Stewartia × henryae' from the website Trees and Shrubs Online (treesandshrubsonline.
Stewartia × henryae was first recognised at the Henry Foundation for Botanical Research, Gladwyne, Pennsylvania, prior to 1964, when it was named in honour of the founder, Mary Gibson Henry (1884–1967). It has since occurred in other collections where both parents are grown, notably at Polly Hill Arboretum and Arboretum Wespelaar. Hsu, Boland & Camelbeke (2008) note that it can have excellent autumn colour.
Most clones of S. × henryae fall short of equalling S. pseudocamellia but this selection from Polly Hill Arboretum is highly regarded for its fastigiate habit, free-flowering with abundant smallish flowers (3.5 cm diameter) and good red autumn colour (Hsu et al. 2008, PlantLust.com accessed 16 July). It was a seedling from commercial seed sown in 1959, planted out in 1963 and first flowering in 1969. By 1991, it was 9–10 × 3–4 m, forming a narrow vase-shaped tree on a richly coloured trunk (Polly Hill Arboretum). Although Hsu, Boland & Camelbeke (2008) state that is difficult to propagate, it was available from several US nurseries in 2016, and it is cultivated at Arboretum Wespelaar.