Plant of the month for July 2016
Sweetshrubs: Spectacular new varieties have great potential and are something of a rarity.
The 7 to 10 cm wide lotus-shaped flowers of these interesting new varieties are sure to attract attention. Both hybrids originated from 1991 by crossing Calycanthus floridus, the American sweetshrub and the Chinese sweetshurb, Sinocalycanthus chinensis, in the JC Raulston Arboretum at NC State University in Raleigh, North Carolina. The variety bears the name raulstonii in honour of JC Raulston, director of the NCSU arboretum.
Richard Hartlage, an employee of the NCSU arboretum, who carried out the hybridisation, is the patron and contributed to the variety name of the burgundy flowering variety Sinocalycanthus raulstonii, ‘Hartlage Wine’. Sinocalycanthus raulstonii, ‘Venus’ has white to creamy white flowers with a subtle, wine-coloured inner pattern.
Both varieties are truly delightful especially with star and magnolia-like flowers that are much larger than the parent species of the two varieties. The flowers are also suitable for arrangements and vases.
The large, dark green shiny leaves of these two new varieties are reminiscent of the male parent Calycanthus floridus. The leaves give off a pleasant, aromatic fragrance. The autumn colouring is accompanied by foliage in yellow-gold nuances.
They are excellent garden shrubs that blossom throughout the entire year after the main blooming period in June/July. Like their relatives, they are happy in the partial shade offered by trees or buildings and grow to about 2 to 3 meters high when growing upright and just as wide with slightly overhanging branches. Both varieties are very low maintenance in terms of care, prefer not too dry, nutritious low alkaline to acidic, humus-rich soils. The root is fleshy and flat, the shoots are later covered with many white lenticels.
This quite new hybrids from the USA are currently still a rarity and will increasingly be used particularly in design in the future. Light protection in winter is recommended for young plants.