Effects of Photoperiod Treatments on Stock Plants and Cutting Rooting of Winecups

A BSTRACT . Production of attractive and water-efficient plants native to the plains and prairies of central North America can sometimes be limited because of problems associated with successful rooting of vegetative cuttings. Winecups ( Callirhoe involucrata) ) is an attractive native plant, valued for its long period of bloom, drought tolerance, and winterhardiness, but can be difficult to propagate from seeds and vegetative cuttings. Seed dormancy issues can result in unreliable germination and seedling variations, which reduces crop uniformity. Although propagation from rooted cuttings maintains crop uniformity, cuttings often fail to root or root poorly. Manipulating the growing conditions of stock plants to suppress reproductive growth may improve rooting success of vegetative cuttings. Based on research conducted earlier with other ornamental perennials and programmed photoperiods, winecups plants were grown under three programmed photoperiods to determine if a particular photoperiod could be used to suppress reproductive growth and promote vegetative growth. The study consisted of three experiments, all conducted in similar fashion but at different times during the year. Results indicate that plants grown under 10-hour and 8-hour photoperiods remained vegetative longer when compared with plants grown under 12-hour photoperiod. Vegetative cuttings harvested from plants grown under 8-hour photoperiod had higher percent rooting when compared with vegetative cuttings harvested from plants grown under 10-hour and 12-hour photoperiods. Based on the findings from this research, plant propagators may be able to increase production of winecups by growing stock plants under 8-hour photoperiod.