Abstract

Six different container designs were evaluated for their effectiveness in minimizing or preventing the development of circling roots around the sides and/or bottoms of containers. While both shrub and tree species were tested, the roots of the shrubs were generally small and fibrous enough that selection of a container to minimize or prevent circling roots was not an important consideration. For the tree species, the greatest amount of circling reduction was achieved with the soft polybags and the rigid stepped-pyramid containers. Because considerable difference exists in the cost of the newly-designed containers, both cost and root-modifying effectiveness should be considered if root modification is deemed important.