And so it begins, the season of flashier flowers than the subtle clematis beauties of winter. Often the first amongst these is ‘Constance’, in the clematis horticultural group known as the atragenes (at-rah-jen-knees). This group contains species such as Clematis alpina, chiisanensis, fauriei, koreana, and macropetala, and are often referred to as the “little bells” of spring. Most have only four sepals, but when the double C. macropetala is involved in the breeding, the resultant hybrids are likely double, too.
Such is the case with ‘Constance’. This culitvar is consistently one of the earliest to bloom in the Rogerson Clematis Garden’s Spring Border. Our specimens, as seen here, clamber though a long hedge of Viburnum tinus. Any pruning of ‘Constance’ is done directly after the first flowers have faded. With a bit of fertilizer added at pruning time, ‘Contance’ will bloom again in August, and will likely produced a modest autumn show in early October.
‘Constance’ is named for the British actress Constance Cummings, and was raised from a seedling of C. ‘Ruby’ by a family friend of Ms. Cummings, Kathleen Goodman of Hull, UK. The plant was introduced to the trade in 1992, and had rapidly established itself as a favorite of this group. The vines can reach 12′ tall if left unpruned, but can be maintained at a more modest 6-8′ with a good tidying, as mentioned above, done directly after the first round of flowering is over.
As if the plant needs further selling points, it would be remiss of us not to mention how very tough the “little bells” of spring are. The winter hardiest of all clematis, Clematis siberica (yes, as in Siberia), takes winters to Zone 2-3. The rest of the species can take winters down to zones 3-4 with little or no damage.
Interestingly, what this group does not like is excessive winter warm. In the humid areas of Zone 8, and in Zones 9-11, all of the atragenes are expensive annuals. Without winter cold to reset their bloom cycle, and in areas where summer temperatures do not drop at night, the plants bloom themselves to death in a year’s time. While we grow ‘Constance’ and her cousins to perfection here in the greater Portland area, in Atlanta, GA, also zone 8, she is doomed to failure because of the summer heat and humidity, which is not factored into USDA zone designations.
However, in Denver, or out on the prairies, or in the high desert areas of eastern Washington and elsewhere, the atragenes will be the most cast-iron of the clematis commonly available for sale.