Effects of flurprimidol and daminozide on growth and flowering of oriental lily ‘Mona Lisa’

Two separate experiments were conducted to evaluate the effectiveness of growth retardants in controlling height of oriental lily ‘Mona Lisa’. In first experiment flurprimidol was applied as a single foliar spray (0, 10, 20, 30 and 40 mg l⁻¹) or a soil drench (0, 0.1125, 0.225, 0.3375 and 0.45 mg/pot) at two plant growth stages (7 and 15 cm). In second experiment flurprimidol (0, 10, 20, 30 and 40 mg l⁻¹) and daminozide (0, 2500, 3500 and 4500 mg l⁻¹) were applied once or twice as a foliar spray. Daminozide applied once or twice at concentrations of 2500–4500 mg l⁻¹ was ineffective in ‘Mona Lisa’ growth retardation. Flurprimidol was effective growth retardant in reducing stem extension without adverse side-effects. The maximum reduction in plant height obtained was 45% compared to controls. Flowering time was not affected by lower rates of flurprimidol, but it was slightly delayed when retardant was applied at higher doses. The tepal size, leaf size and pedicel length were smaller than those of the control plants. Intensified leaf colour was observed on flurprimidol treated ‘Mona Lisa’. The effect of flurprimidol persisted in the year after treatment.