The primary purpose of a good planting area is to provide sufficient air to the plant roots. As a general rule, if you are planting trees and shrubs in individual holes, do not add any soil amendments...simply fluff the existing soil. If you are planting in large beds, use all of the organic amendments that you can afford but these should be thoroughly mixed with the existing soil, and not simply piled on top. This allows for an extensive well-prepared root zone in which the plant roots will remain for most of their lives.
No matter what kind of soil you have, be careful not to install your plants too deep. They should never be planted any deeper than they were grown in the nursery. Planting too deep is a common problem, and thousands of plants are killed each year by gardeners who just don't understand how critical the planting depth is.
It is a mistake when planting a bare-root tree, to prune away some of the branches to balance the top with roots lost when the tree was dug up. When a bare-root tree begins to grow, it's able to limit new shoot and leaf growth to the capacity of the root system on its own. Pruning takes away some of the healthiest buds and robs the tree of stored energy. If, however, a new tree has a broken limb, prune it back to the nearest strong bud or side shoot. After the tree has grown for a season and recovered from the stress of transplanting, begin pruning for a balanced shape with well-positioned main limbs. Use the least number of cuts possible.
Plants should never be potted up into pots without drainage holes; a layer of gravel will do nothing to stop the soil becoming waterlogged. If the soil in the bottom of a pot stays wet, a plant's roots will get waterlogged and rot. But it's the holes in the bottoms of containers that allow the water to flow through. In fact, any gravel in the bottom reduces the volume available for potting soil, as well as making everything heavier than it needs to be. All that is required is a small fragment of terracotta over the pot's drainage holes to keep the soil from slipping out. If the pot rests in a shallow saucer, don't habitually keep the saucer full of water or roots in the bottom layer of soil will be damaged.
After planting an evergreen shrub, spray the foliage every day for two weeks. Use annual climbers to cover a bare trellis while the slower-growing plants get a chance to establish.
Protect tender perennials from frost by lining a pot or basket with straw and placing it over plants when frost is likely to strike.
For a large pot planted with a shrub, such as Box (Buxus) or Bay (Laurus), surrounded by lower growing plants, keep the shrub inside a plastic pot rather than in the pot soil, you can then replant around it regularly without disturbing the shrub's roots.
