Calibrachoa
Calibrachoa hybrids
Calibrachoa, sold under the trade name Million Bells and many similar Superbells, MiniFamous, Aloha, and Cabaret series names, is a tender perennial in the petunia family grown as a summer annual in Alberta. Tiny petunia-like trumpets in nearly every colour including yellow, orange, coral, magenta, deep purple, near-black, and bicolours. A workhorse for Edmonton hanging baskets, window boxes, and containers from May through hard frost. Modern hybrids are self-cleaning (no deadheading required), tolerate heat better than petunias, and bloom non-stop if fertilized regularly. The single most common cause of failure in Edmonton is starvation, since these are heavy feeders that exhaust the nutrients in commercial container mixes within a few weeks. Treat them right and they will cascade for the entire season.
Quick Facts
Distribution
Annual in Alberta (perennial in zones 9+). Native parents from South America, primarily Brazil and Argentina.
Light
Full sun. Will bloom in part sun but flower production drops sharply with less than 6 hours of direct light.
Bloom Time
Continuous from May/June planting through first hard frost (typically late September in Edmonton).
Soil
Light, very well-drained, slightly acidic potting mix (pH 5.5 to 6.0). Calibrachoa is one of the few container plants that prefers a slightly acidic mix; alkaline tap water and Edmonton's calcium-rich soil push it into iron deficiency, showing as yellowing leaves with green veins.
Water
Consistent moisture but never soggy. Containers in full Edmonton sun may need water twice daily in July heat. Avoid wetting foliage in the evening to prevent fungal issues.
Growing & Cultivation
Best Planting Time
Plant out from nursery cell packs or potted starts in mid to late May, after risk of hard frost. Light frost (-2 C) is tolerated by hardened-off plants; a hard frost will kill them.
Propagation
Modern Calibrachoa cultivars are patented and propagated commercially from tip cuttings. Home propagation by stem cuttings in summer is technically possible (root in moist perlite under plastic) but legally restricted on patented varieties. Most gardeners simply buy fresh plants each spring.
Pruning / Splitting
No deadheading required (self-cleaning). If a basket gets leggy by midsummer, cut it back by one-third, fertilize, and it will rebloom within 10 to 14 days.
Spacing
20 to 30 cm in containers (3 plants per 25 cm hanging basket is standard).
