Medium Temperature Influences the Rooting Response of Hibiscus rosa-sinensis L.

Abstract Adventitious rooting of stem cuttings of Hibiscus rosa-sinensis L. ‘Pink Versicolor’, ‘Brilliant Red’, ‘Jim Hendry’ and ‘Silver Anniversary’ was evaluated after propagation at medium temperatures of 18°, 22°, 26°, 30° and 34°C (65°,72°,79°,86° and 93°F). Cuttings of all cultivars propagated at medium temperatures of 26° and 30°C rooted faster and developed more roots with larger fresh and dry weights. Rooting percentages for each cultivar was similar among all propagation medium temperatures, but 26° and 30°C (79° and 86°F) reduced the weeks required for rooting 50% of the cuttings and periods in weeks between 10% and 90% rooting. The most vigorous rooting ‘Pink Versicolor’ had more uniform root emergence and the best response at unfavorable medium temperatures, while the poorest ‘Silver Anniversary’ had inconsistent root formation at all temperatures.