Effect of stock and grafting method on successful graft union in rhododendrons

Grafting plays an important role in rhododendron propagation. Successful graft union depends on selection of a suitable stock, grafting season, and method. In this study, three methods (whip, cleft, and side grafting) were compared in two seasons. The stocks were mainly cuttings of R. catawbiense-Hybridum, R. ‘Cunningham's White', but also R. pachytrichum and R. brachycarpum. Scions were taken from several cultivars deriving from R. catawbiense. To shorten the production period, scions were grafted on unrooted stocks, and the results are encouraging. The best stock was R. ‘Cunningham's White', especially when side grafting was applied in spring.