Consider several factors when selecting containers and trees including environmental influences, container and planter design, substrate type, and tree characteristics. Environmental influences Hardiness is the ability of a tree to survive in a particular geographic area, with temperature being the major determining factor. Tree roots are generally several degrees less cold hardy than tree stems. This means that roots of trees in containers and planters, whose stems might ordinarily be hardy to sub-zero temperatures, may die when substrate temperatures drop below freezing. If the substrate freezes, wind may cause leaves on evergreen trees to dry out because roots are unable to absorb water from the frozen root ball.
Wind can also speed container substrate temperature decreases.
Wind, as well as heat from pavement, can increase water evaporation from containers, leading to dried out leaves. Container and planter design and size Containers and planters for landscape trees can be constructed of a variety of materials in many different shapes and configurations. Coordinate the appearance of containers and planters with the landscape site. Also, determine how much time and money is available for container and planter maintenance and select accordingly. With regard to container or planter size, a confined tree root system ideally should have two cubic feet of substrate for every square foot of tree canopy.