Effect of root pruning and planting depth on growth and root ball quality in container production of royal poinciana (Delonix regia)

Abstract

Increasingly, producers and consumers are realizing that roots play a major role in tree quality and that quality begins in the nursery. To remain competitive, producers need to fi nd economically viable methods of producing trees to meet rising quality standards, particularly with regard to root systems. Three different root pruning methods and two planting depths were evaluated as 1-gal container-grown Royal Poinciana Delonix regia were shifted into 7-gal containers. Root pruning had no impact on trunk caliper or tree height and no impact on primary root diameter. Root pruning increased the number of straight roots inside the root ball but had no impact on the percentage of the trunk encircled by roots. Trees planted with the topmost root 4 inches below the 7-gal substrate surface had more root defects than trees planted with roots close to the surface.