Rooting potential of the ‘vleitee’ honeybush (Cyclopia subternata) as affected by growth season and the manipulation of stock plant characteristics

Abstract

To ensure a high-quality, sustainable supply of South African indigenous honeybush (Cyclopia spp.) tea to domestic and international markets, a shift from wild harvesting practices to true-to-type clonal material is required. This study investigated the impact of stock plant rejuvenation period and seasonality, and the harvesting position of cutting material on stock plants, on the rooting success of four genotypes of Cyclopia subternata Vogel, the most widely cultivated honeybush species. Cutting rooting success varied between 65–94% in summer and 49–91% in autumn, whilst winter-rooted cuttings showed poor rooting success (0–7%). Cutting dry weight was positively correlated with rooting percentage (r = 0.647; p ≤ 0.001). The rooting success of cuttings was strongly impacted by internal stock plant factors, such as clonal effects, cutting position and rejuvenation period. The use of terminal, semi-hardwood cuttings collected in autumn, following 15 months of regrowth, is recommended to achieve acceptable-to-high rooting success. This study confirms that the clonal propagation of C. subternata via cuttings could be a viable option for the sustainable production of high-quality honeybush tea, provided the selection criteria of the stock plant material used as the cutting source is carefully considered.