A hybrid between “C. floribundus” and C. ‘Indigo’ raised by Messrs Burkwood and Skipwith of Kingston-on-Thames. The first parent was presumably either a form of C. dentatus or C. × veitchianus, but owing to the confusion over the name “C. floribundus” its identity is uncertain. The second parent – ‘Indigo’ – is a hybrid of the C. × delilianus group. This hybrid is therefore of particular interest as uniting in itself the two sections of the genus, viz. those that flower in spring on the growths of the preceding year (as in the evergreen Californian species) with those that flower in late summer and autumn on the growths of the current year (as in ‘Indigo’ and its parents and fellow hybrids).
An evergreen bush probably 5 or 6 ft high, richly leafy, Leaves rather shining green and glabrous above, greyish and downy beneath; oval, rounded at both ends, toothed, 1⁄2 to 11⁄4 in. long, about half as much wide. The chief veins are prominent beneath and number four or five each side the midrib, the basal pair usually the strongest and showing derivation from a species of the three-veined group. Flowers rich bright blue, in panicles 1 to 21⁄2 in. long, opening from July to October. Each blossom is about 3⁄16 in. wide, the petals ladle-shaped; stamens and style deeper blue than the petals; anthers pale yellow.
C. ‘Autumnal Blue’, raised by the same firm, is another hybrid of the same type but has C. thyrsiflorus as one of its parents. The leaves are larger than those of ‘Burkwoodii’, more glossy green, and quite distinctly three-veined. The flower trusses are larger and paler in colour.
Both these are distinct and beautiful acquisitions to late-flowering shrubs, and both, according to the raisers, have withstood 320 of frost uninjured, although growing without shelter in the lower Thames Valley. Like all their race, they should be given a sunny position. The Cory Cup, given to the best artificially raised hybrid of the year, was awarded to C. ‘Burkwoodii’ in 1930.