Influence of Stock Plant Growing Environment, Origin of Cuttings, Cultivar, and Rooting Hormone on Clematis Cutting Production and Propagation

Abstract

Clematis (Clematis ×hybrida) has not traditionally fit into the standard production system for vegetatively propagated herbaceous perennials because of the lack of commercially available unrooted cuttings and relatively poor rooting success. We investigated strategies to improve stock plant production and propagation of clematis. The first experiment compared the propagation performance of four cultivars (H.F. Young, Reiman, Little Duckling, and Pinky). The second experiment examined cutting productivity and propagation performance of clematis cultivars when stock plants were grown at 21 or 27 °C and propagated with or without the application of rooting hormone. Stock plants grown at 27 °C resulted in greater cutting numbers and greater dry weights in the rooted cuttings after propagation. The third experiment demonstrated the effects of the origin of the cuttings of the stock plant on cutting productivity and propagation performance. When shoots emerged from underground buds, as compared with axillary buds, the numbers of cuttings and fresh and dry weights of the rooted cuttings were increased by nearly 50%. The promotion of shoot emergence from underground buds on the stock plants led to continuous cutting production for five cycles, with cutting number increasing from 67 to 128 cuttings/plant. Year-round cutting supplies can be achieved by trimming stock plants to the substrate surface to promote juvenile shoot development while maintaining stock plants under long-day photoperiods and warm temperatures (27 °C).

Effects of Photoperiod Treatments on Stock Plants and Cutting Rooting of Three Cultivars of Ornamental Perennials

“…Hartmann et al (2017) noted that cutting propagation is the most important means for clonal regeneration of many horticultural crops, and adventitious root formation is a prerequisite to successful cutting propagation. Samarakoon and Faust (2022) noted that poor rooting is a common phenomenon for many perennial species, and attributed poor rooting to juvenility, seasonality, bud dormancy, and/or cultivar. The juvenile phase of a plant can be as short as a few days (in some herbaceous species) or can extend to several years (in some woody species).…”