Group 1
Early – small flowers, evergreen; Montana – vigorous, large small flowers
Group 2
Early cultivars, larger flowers, early to late summer
Group 3
Late large flower cultivar; Late flowering species
Potential options from Group 2 (earlier)
- C. The President
- C. Lasurtern – lavender, large
- C. Nelly Moser – rose-mauve
- C. Niobe
Potential options from Group 3 (later)
- C. Ville de Lyon
- C. Hagley Hybrid – mauve, vigorous
- C. Jackmanni (Superba) – purple, large
- C. Perle d’Azur – blue
- C. rehderiana – yellow bell flowers
- C. tungutica – yellow bell flowers