When I go to a nursery to buy a tree or shrub, I'm looking for a plant that will make steady progress and endure, not one that will cling to life for a season or two then have to be replaced.
Years of experience have helped me hone my detective skills and I've developed an almost fool-proof method of choosing the healthiest specimens for my landscape. You can become a savvy shopper, too, by following these same guidelines.
The shape of a plant is an indication of its health. The branching should be balanced on all sides of the plant and the foliage should be full. Make sure upright trees, such as pine and spruce, have a trunk with a healthy tip (leader). If the leader is dead, it's hard to grow a straight tree, though you can encourage a new leader by training a top branch vertically.
Look for good foliage color. It should be uniform throughout the plant, except for new growth. Yellow color or brown edges or tips indicate root damage from improper watering or fertilizing. If whole branches droop, the plant may be dry, over-fertilized or over-exposed to sunlight.
A sure sign of good health is new growth. Look among the plant's branches for soft, green tissue with tiny new leaves. The new stems should all be the same thickness and the new leaves should be about the same size and spaced at equal distances along the branches. If some of the leaves are smaller or farther apart, or if the stems are spindly, the plant is probably not receiving adequate care.
Nurseries sell trees and shrubs in containers or balled-and-burlapped (their roots and a small amount of soil are wrapped in burlap and tied). Balled-and-burlapped plants are grown in the ground and are usually lifted every year and root-pruned. When it's time for them to be sold, they are dug up with a good amount of earth attached to the roots and wrapped in burlap. Because of the annual root-pruning, balled-and-burlapped plants develop a compact root system with lots of feeder roots. They aren't root-bound, so they're more likely to transplant successfully than root-bound container-grown plants. However, the labor involved in annual digging and root-pruning makes balled-and-burlapped plants more expensive.
Container-grown trees and shrubs have one potential advantage ?- their roots are protected by a container and are less likely to be injured or broken when the plant is moved. And, when the plant outgrows its container, the entire root ball is dropped into a larger container, resulting in less trauma to the roots. As long as container-grown plants are transplanted into larger pots as required, they'll develop strong, healthy root systems. If they don't receive adequate care, they'll develop too many roots for the size of the container and become root-bound. When roots twist around themselves, they can strangle the plant. The best way to check if a plant is root-bound is to gently slide it out of its container. The roots should fill the container without being crowded, and the root ball should remain intact after being unpotted.
Before you make that final purchasing decision, check trees and shrubs for diseases and insects. Look at the undersides of leaves and along the growing tips, then carefully check the branches. The plant's foliage and stems should be absolutely free of insects and disease. Check for holes and other signs of trouble, such as webbing on the undersides of leaves, black blotches, red or yellow spots, holes surrounded by discoloration, or mottled leaf surfaces.
Trust what the leaves, stems and roots tell you. Check the top growth first, and then examine the roots. If the roots aren't healthy, the plant will have a tough time adjusting. As long as the plant you like passes these health tests, go ahead and buy it. Your investment should provide years of beauty in your landscape.
Photograph by Patt Kasa/National Gardening Association.