Planting Date and In-ground Time Affect Cut Flowers of Liatris, Polianthes, and Iris

Abstract

Bulbous roots of Kansas gayfeather or liatris (Liatris spicata Wind.), tuberose (Polianthes tuberosa L.), and Dutch iris (Iris × hollandica) were planted between Nov. 1986 and Mar. 1987. Late planting extended harvest times and resulted in highest yields and longest stem lengths for Liatris spicata and Polianthes tuberosa, but. results were cultivar-dependent with Iris × hollandica hybrids. Yield was highest for all cultivars of Dutch iris except `White Bell' when bulbs were planted in December. Late planting extended harvest time but reduced yield for all cultivars except `White Wedgwood'. No differences due to planting time occurred after the first season for liatris and tuberose, but both species had higher yields the years after initial planting and may be left undisturbed for at least 3 years. Iris flowers were destroyed by late frosts in two successive years and longevity could not be determined. The yield and stem length were optimum for Liatris 10 to 15 days from beginning of harvest, 4 to 5 weeks for single-flowered tuberose, and 5 to 6 weeks from start of harvest for double tuberose. Stem length of tuberose increased over the seasons, regardless of cultivar.