Root-bound plants can be identified by larger roots which tend to grow in a circular fashion around the outside of the root ball. Root-bound plants aren't likely to produce a healthy, spreading root system needed for proper plant development. It's best to pay more for top quality nursery stock with healthy roots. Crown gall is caused by a bacterium and can occur on roots, trunks, and limbs of infected fruit and nut trees. The galls, which range in size from small swellings up to 1 or 2 inches in diameter, are most commonly found where the main plant stem enters the soil.
Galls are normally dark brown to black and have a roughened appearance.
They cut down the amount of water moving from the roots to the upper plant parts and eventually cause plant death. Root-knot nematode infections on plants are more difficult to detect. The small swellings on roots, caused by the feeding of nematodes, are the same color as the roots. Unless the root system is carefully examined after removal from the container, root-knot infections can be easily overlooked. Consequently, severely infected plants become stunted and produce poor yields.