Effects of Collection Time and Environment on the Rooting of Lingonberry (Vaccinium vitis-idaea L.) Stem Cuttings

Methods to promote the rooting of lingonberry (Vaccinium vitis-idaea L.) stem cuttings were investigated, including (1) the optimum time (April-August) for collecting cuttings of the commercial cultivar Sanna, and (2) three different environments: heated greenhouse (18°C), and outdoor plastic tunnels with and without bottom heat. Considerable variation in the effect of collection time was obtained between years. The highest rooting percentage (90%), including all environments determined after 30 days, occurred in 1993 on plant material collected early in the season. In 1994 material collected later rooted better. Overall rooting percentage was higher in the outdoor plastic tunnels than in the greenhouse. In tunnels, rooting was improved by bottom heat, which accelerated the rooting process. Softwood cuttings required more time to form roots than did hardwood cuttings.