The 2012 ASHS Annual Conference

Several non-traditional, “air-root-pruning” container types are available to growers that purportedly enhance growth of shrubs and trees by manipulating soil aeration and root growth to produce a better root system for outplanting in the landscape but also for potting up into larger containers. In a two-year study at a California nursery, three non-traditional, root-pruning container types produced mixed results but none produced significantly greater root mass, leaf or stem growth, or overall quality than a standard container for production of kentia palms [Howea forsteriana (F. Muell.) Becc.] and king palms [Archontophoenix cunninghamiana (H. Wendl.) H. Wendl. & Drude]. With one of the air root pruning containers, we observed a more uniform root system with denser but shorter secondary roots that may confer a survival advantage when outplanting, but was not investigated in this study. Generally, palms in larger containers tended to produce more growth and were of higher quality than those in smaller containers. When examining treatment effects over time, there were no advantages of using root-pruning containers for enhanced early leaf or stem caliper growth.