Propagation of Firebush (Hamelia patens) by Stem Cuttings

The influence of bottom heat, rooting medium, type of cutting (i.e. terminal vs. subterminal), and commercial auxin formulations on greenhouse propagation of firebush (Hamelia patens Jacq.) by leafy stem cuttings during winter was investigated. Without bottom heat, mid-day rooting medium temperature averaged about 22 ± 3°C (72 ± 5°F). Percent rooting of auxin-treated cuttings without bottom heat was 50% and mean length of the longest root and visual rating scores of root development were low. Maintaining the rooting medium at 29–39°C (85–10 1°F) increased percent rooting for auxin-treated cuttings to 96–100% and increased root length and visual rating scores several-fold. Rooting percentage, root length, and visual rating scores were consistently high in perlite and low in peat moss. Terminal stem-tip cuttings and subterminal stem segment cuttings with basal stem diameters of 3–5 mm (0.13–0.20 in) rooted slightly better than subterminal stem segment cuttings which had basal stem diameters of 6–8 mm (0.25–0.32 in.). Terminal stem-tip cuttings not treated with auxin but with bottom heat had rooting percentages of 81–86%. Treatment of terminal stem-tip cuttings with Rootone F or Wood's Rooting Compound (1:20 or 1:5 dilution) generally resulted in rooting percentages above 90%. Some of the auxin treatments also resulted in increased root length and visual rating scores. Despite these differences, none of the plants grown from auxin-treated cuttings, were distinguishable from plants grown from nontreated cuttings two months after the rooting period. Of the variables studied, bottom heat had the most dramatic effect on rooting of stem cuttings during winter months.