Effects of Pruning Height on Axillary Bud Development in Dracaena Cultivars ‘Waikiki’ and ‘Ruth Luka’ Grown from Stem Cuttings

Abstract

The ability of a single rooted cutting to produce multiple shoots, when pruned to various heights, using newly introduced Dracaena cultivars ‘Waikiki’ and ‘Ruth Luka’, was studied. Well-rooted cuttings were pruned to either 5.08 centimeters (cm), 15.24 cm, or 25.4 cm (2, 6, or 10 inches) height and were grown in a climate-controlled greenhouse under either 30% or 60% shade. When grown under 60% woven shade, all D. ‘Waikiki’ rooted cuttings pruned to 5.08 cm (2 inches) produced two axillary bud breaks per plant; for D. ‘Waikiki cuttings pruned to 15.24 cm (6 inches), 83% produced two axillary bud breaks and 17% produced only one bud break; for D. ‘Waikiki’ cuttings pruned to 25.4 cm (10 inches), 50% of the plants produced two bud breaks and 50% produced one bud break per plant. When grown under 60% woven shade, D. ‘Ruth Luka’ pruned to 5.08 cm (2 inches) produced only one bud break on 92% of plants while 8% of plants produced two breaks; for D. ‘Ruth Luka’ cuttings pruned to either 15.24 or 25.4 cm (6 or 10 inches), 83% of plants produced one bud break and 17% of plants produced two bud breaks. Unpruned plants of both cultivars grown under 60% shade did not produce any axillary shoots. When well-rooted cuttings of D. ‘Waikiki’ were grown under 30% knitted shade, 67% of the plants pruned to 5.08 cm (2 inches) produced two bud breaks while 33% of the plants produced only one bud break; for D. ‘Waikiki’ cuttings pruned to 15.24 cm (6 inches), 58% produced two bud breaks while 42% produced one bud break; for D. ‘Waikiki’ plants pruned to 25.4 cm (10 inches), 42% of plants produced two bud breaks while 58% produced one bud break. When well-rooted cuttings of D. ‘Ruth Luka’ were grown under 30% knitted shade, 8% of the plants pruned to 5.08 cm (2 inches) produced four bud breaks while 8% produced three bud breaks, 76% produced two bud breaks, and 8% produced one bud break; for D. ‘Ruth Luka’ cuttings pruned to 15.24 cm (6 inches), 8% produced three bud breaks, 25% produced two bud breaks and 67% produced one bud break; for D. ‘Ruth Luka’ plants pruned to 25.4 cm (10 inches), 8% produced four bud breaks 8% produced three bud breaks, one of which was a sucker from beneath the surface of the soil, 67% produced two bud breaks, and 17% produced one bud break. Unpruned plants of either cultivar grown under 30% knitted shade did not produce any axillary shoots. For the 60% shade environment, a grower could confidently expect two breaks on well-rooted stem cuttings of D. ‘Waikiki’ when they are cut back to 5.08 cm (2 inches), but as pruning height is increased, the number of breaks will tend to decrease to one. By comparison, D. ‘Waikiki’ has more attractive leaf colors and growth habit when produced in a greenhouse under 30% knitted shade than when produced under heavier shade or full sun. A grower could also be confident that well-rooted stem cuttings of D. ‘Ruth Luka’ grown under a 30% knitted shade environment and pruned to 5.08, 10.24, or 25.4 cm (2, 6, or 10 inches), respectively, would produce at least two breaks per stem, but possibly up to four axillary shoots. Dracaena ‘Ruth Luka’ may also produce axillary shoots with different levels of green or with striped variegation. The information determined from these experiments could help foliage growers determine how pruning height might affect shoot production of various rooted dracaena cuttings grown under various light levels.