Leaves green. Adult plants usually more than 1 m tall and broad. The flowers on one plant are simultaneously of two or more colours (i.e. white and red, white and purple, yellow and red). The standard cultivar is ‘Courtalor’ (syn. ‘Carnaval’) (Hoffmann 2008).
Weigela florida 'Bicolor'
There are potential problems around the use of the cultivar name ‘Bicolor’. Although Hoffmann (2008) treats it within the Bicolor Group, the extensive checklist produced in 1965 (Howard 1965) lists two occurrences of the name ‘Bicolor’: one under W. coraeensis, which was offered by the Daisy Hill nursery in Newry, Northern Ireland ‘with rose and creamy white flowers on the same bush’, and another under ‘W. middendorfiana bicolor. The lower lip of the corolla marked and dotted with purple’, which had been offered by the firm Parsons and Sons, New York.
Modern descriptions of ‘Bicolor’ better match the first of these entities, although nowadays one sees it associated with W. florida rather than W. coraeensis when an author insists on assigning it to a species.
An early selection, raised by Billiard at Fontenay-aux-Roses, France, in about 1868. The flowers are dark purple-pink in bud, then purple-pink with a large white border, darkening to purple-red with age. They are also strongly scented, a relatively unusual trait. The leaves are described as having long-acuminate apices (Howard 1965).
A rounded shrub with a height and spread of c. 0.9–1.2 m, which simultaneously bears white and pink two-toned flowers, and red flowers. It is a triploid hybrid, which arose in France from a cross of ‘Abel Carrière’ and ‘Bristol Ruby’ (Hillier & Coombes 2002; Hatch 2017).
Raised at INRA in Angers, France, this is a relatively low growing but wide-spreading shrub with flowers, which are dark purple-red in bud, yellow-white when first open, and maturing to red later (Hoffmann 2007). In his 2007 paper, Hoffmann places this selection in the Bicolor Group, but in his 2008 paper it has moved to the Variegata Group. In his key, Hoffmann gives precedence to leaf colouration over flower colouration, but offers no description of the leaves for us to make an assessment, so for now it is tentatively retained in the Bicolor Group.
Weigela japonica 'Intercol'
A large shrub and one of the largest of the weigelas, to 3 m tall and nearly as wide. The foliage is also remarkably large for the genus, yet the flowers are quite modest, typically to 2.5 cm across. They are pale-yellow at first, with a darker yellow throat, irregularly turning yellow-pink then pink-red. Raised at Darthuizer Boomkwekerijen BV., Leersum, the Netherlands in c. 1987 (Hoffmann 2007).
Deep pink and white flowers are borne simultaneously. Apparently this selection is inferior to ‘Courtalor’ (Hatch 2017).