Choosing a Plant at the Nursery
When selecting a container-grown plant, notice the container size in relation to the plant. The container should be large enough to hold a root system without over-crowding it. If possible take the plant out of the container to see if it already has many circling roots and is “pot-bound." If so, you might want to look for another plant. You can also ask the nursery if they are using new containers that air-prune roots or containers painted with “Spin-out” that reduces circling roots.
Fix those Roots before you Plant
If you did purchase a pot-bound plant, don’t worry, with attention to the roots, your plants will survive and thrive. In most pot-bound container plants, there is a mass of roots at the base of the container. By hand or with a garden spade remove the mass. If the whole container is lined with roots it is best to tear the roots apart by hand. If the roots are very compact and dense, it is necessary to take the garden spade and cut through the bottom half of the ball vertically. The purpose is to expose more root area and promote root regeneration. The roots will now be able to grow out into the soil.
Avoid Transplant Shock
Trim foliage. To give the roots the most energy to regenerate, trim back some of the foliage of the plant.
Water. This is very critical to the survival of the plant. Apply water at the base of the plant. Soilless media dries out quickly (in which many nursery grown plants are started); therefore, a thorough soaking is necessary until the plant is established.
Mulch. Adding mulch around the plant base (not touching the stem) will keep the shallow fine rooted plants cooler in the summer heat and act as insulation during the cold winter. Use any course material such as woodchips, bark, pine needles, etc. Course textured mulch will allow water to pass through to the roots below.