NURSERY PRODUCTION OF TREES IN CONTAINERS1 by William Flemer III Princeton Nurseries

--The possibility of growing sizeable shade trees (1%" and over in caliper) in containers is exciting to both arborists and nurserymen. Advantages include reduction in transplant shock, ease of retail storage, extension of the planting and shipping seasons, and less need for nursery space. However, problems include difficulty in overwintering in northern climates, root girdling, potbound trees, and the high cost of growing mix and containers. The suggested best method for cold-weather zones is to re-establish large trees in containers. THE PRODUCTION OF sizeable shade trees (1%" in caliper and up) in containers has long been a greatly desired goal of arborists and nurserymen alike. It has also been of great interest to the operators of retail garden markets because the storage and handling of bare-root trees at the retail level is a practical impossibility. The arborist is enchanted by the idea of receiving trees thoroughly established in easily removeable containers, trees with every root intact, with a complete balance between root and crown, and not subject to any transplanting shock. Further attractions are the ability to extend the planting season to any time of the year that the ground is not frozen deeply, thus permitting fuller utilization of a smaller, thoroughly experienced planting crew and also permitting additional tree planting whenever budgetary surplusses show up at the close of a fiscal year. Container production also has marked advantages for the grower, the most important one being some relief during brief, hectic digging and delivery seasons, because in effect the trees are "dug " or prepared for shipment when they are planted in the container in which they will be sold. Because container-grown stock can be moved safely throughout the year, the shipping season is enormously extended and the grower can employ a smaller, more stable, and better trained work force. Furthermore it is possible to produce a vastly greater number of trees in containers on an acre of land than on an acre in the open ground, where row spacing must be wide enough to permit cultivation and digging. 'Metro. Tree Impr. Alliance (METRIA) Proc. 3:15-23, 1980.