Wednesday, 4 July 2007

Canna cultivar Group definitions

The International Code of Nomenclature for Cultivated Plants (ICNCP) regulates the naming of cultivars, cultivar Groups, and graft-chimaerras. Under the ICNCP, a cultivar group is a gathering of cultivars. There may be several reasons to designate a group, for example a group of yellow-flowering cultivars, a group of cultivars with variegated leaves, or a group of cultivars resistant to a particular disease, etc. Also, a cultivar may belong to more than one Group (it may be yellow-flowering, with variegated leaves and resistant to the disease at one and the same time).

At Claines Canna, we are at the stage where we have identified our cultivar groups, proven that they work for us in our 2007 catalogue and web site, but now we need to refine their definitions. Our definitions are shown below, and we would appreciate feedback to allow us to improve on these 'first-cut' group definitions.

Foliage Group
Cultivars, F1 and F2 hybrids, normally with small species-like flowers, but grown principally for their foliage.

Crozy Group
A cultivar group where the flower spikes are arranged close together on the stalk and have narrow to medium petals. There is always space between the staminodes when arranged formally, and the labellum (lip) is smaller than the staminodes, and is often twisted or curled.

The pioneer of this group was Monsieur Pierre Antoine Marie Crozy of Lyons, France, who started breeding Cannas as early as 1862, from stock originally developed by Monsieur Théodore Année, the world's first Canna hybridizer.

They are sometimes referred to as gladiolus flowering cannas, but describing flowers as similar to another genus is not to be encouraged. In the past, they were sometimes called the x generalis L.H. Bailey garden species, but "pretend" garden species have long been replaced by Cultivar Groups in the International Code of Nomenclature for Cultivated Plants.

Italian Group
A cultivar group with large, fragile staminodes. Flowers are arranged somewhat loosely, with wide petals, so wide that there is no space between them, when arranged formally. The labellum (lip) is larger, or at least as large, as the staminodes, unlike the other groups where it is smaller and sometimes curled. The stamen is also much wider than that in the other cultivar groups.

Also, used to be called the "orchid flowering cannas", or ''x orchiodes'' (Liberty Hyde Bailey) garden species, although such "pretend" species are now deprecated in favour of Cultivar Groups. In any event, it is difficult to see the similarity between this group and orchids.

Most of this group obtained its larger sized flowers from the introduction of Canna flaccida in the early 1890's by Carl Ludwig Sprenger in Naples, Italy, followed shortly afterwards by Luther Burbank in California, USA, with the same cross.

Premier Group
This grouping contains cultivars that have a large, circular shape, without significant gaps between the staminodes. Cultivars in this Group are triploids, either produced from a spontaneous or induced mutation during pollination or germination, or from crosses with the Italian group.

Variegated Group
Cultivars with variegated foliage, regardless of what other Group they may belong to.

Conservatory Group
The growing conditions in a Conservatory are quite specialised and do not suit many cultivars, this group have been selected for thriving in this environment, required features being plant vigour, early flowering, foliar appearance, self-cleaning ability and good propagation qualities.

Aquatic Group
Cultivars that thrive as marginal water plants. Characteristically, they will have lance-shaped foliage and long, thin rhizomes.

Miniature Group
Cultivars growing under 0.5m (19") in height, the flowers should be in scale to the rest of the plant.

Agriculture Group
Cultivars grown selectively for agricultural usage, normally for their very large rhizomes and a high starch yield.

1 comment:

  1. Where does variegated end? The RHS definition refers to two separate colours. In Cannas we regularly have 'dark' foliage, which has green and purple, and its variations. Is that variegated?