h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Unless you live in Death Valley, container grown plants can be put into the ground anytime that the soil is workable. In other words, whenever the soil isn't frozen or waterlogged. Plants bought bare root should be either potted or put into the ground as early as possible, as soon after they are purchased as possible, to keep the amount of time the naked roots are exposed to the air to an absolute minimum. A good trick to reduce dessication of the roots is to dip them in a thin slurry of garden soil and water.

Transplanting established trees and shrubs is best done while the plants are dormant, either in the spring or autumn - those lucky enough to live in places where the ground doesn't freeze solid can tinker all winter. Some trees, such as Magnolia and Birch, show a distinct preference for spring planting; but they can still be moved successfully at other times if they are given a little extra care.

Most conifers do their growing in the spring and early summer; so they are best moved at the end of the summer, when they are fairly relaxed about life and there is still time for them to grow new roots before the onset of winter.

Spring bulbs are planted in the autumn. Old, overcrowded plantings should be lifted and divided after they finish flowering, and the tops are starting to yellow. Don't cut the leaves off after the bulbs flower, as the plants are relying on a bit of good photosynthesis time to recover some strength for next year. They can either be replanted straight away, or stored in a cool place until the following autumn.

JTG