In general plants and trees are sold in three different forms: balled; bare-rooted or in containers and the way you asses each plant will go a long way in contributing to future success.
Balling the roots and covering with a hessian burlap material is a process used for trees and much larger plants. Opt for a specimen that has a moist and firm ball approximately 10-12 times larger than the trunk with a snug wrap.
Avoid plants with roots protruding from the wrapping or where the ball is soft or the cover loose and give the tree a gentle wobble. If the trunk moves but the ball stays in place this can be a sign the tree has broken from its roots.
Look for healthy green foliage, supple branches and signs of new growth. The odd dead or broken branch is no reason to avoid buying your tree but if there are more than one or two or evidence of browning or disease then choose an alternative.
Bare Rooted Plants
When selecting this type of plant, ensure the roots are moist and healthy with even distribution and smaller feeder roots growing from the main core.
Look for evidence of recent watering and compare each to choose one that has evidence of new life coming through.
Stems should be well-formed and unbroken and any plants that have pale, white or diseased leaves should be discounted immediately.
Container Grown Shrubs
The key to a high quality container grown plants is in their care so discard any plants that show signs of drying out. Opt for specimens with firm, uniformly moist soil and check to see if any roots are protruding from the bottom of the pot.
Though many feel small roots are a sign of healthy growth, larger protruding roots indicates the plant has been growing in the pot for too long.
Container grown shrubs should be uniform in colour on all leaves, any signs of discolouring or brown on lower leaves or indications of disease are plants that are not going to last.