As the temperatures drop in autumn, the day length decreases and plant sap slows down, thus reducing the shock and trauma that can occur when moving evergreen trees and shrubs that are actively growing. The soil is still relatively warm in autumn, giving the plants a chance to settle in before the weather really turns cold. The roots will continue to grow throughout winter, and in spring the plant will be ready to start shooting new top growth. To help reduce transplant shock, dose your evergreen shrubs and trees with Magnesium sulphate (Epson Salts) two weeks before transplanting. Dissolve 6 tablespoons into 10l of water and water it into moist soil. For large plants apply an extra dose or two. You can also spray the plant with a product called Wilt Pruf to reduce transplant shock. For large shrubs it is necessary to prune them back a bit or the roots that remain will not be able to support the plant, however, in very cold regions do not prune too harshly. Evergreen trees can also be pruned as required. Prepare the new planting holes well in advance so that the soil can settle nicely. Add lots of compost to the soil and a generous sprinkling of bone meal. Tie a piece of string onto the north side of large trees and shrubs so that you can plant them facing the same direction that they were growing in before. Water the plants to be transplanted thoroughly a day or two before transplanting. For large plants, dig a trench around the plant a day or two before lifting, this is important as you will sever some roots and this is already a shock to the plant. Water lightly and let the plant rest until the following day. Finally dig the entire plant out and move it into its new position. Plant it firmly, stake if necessary, and water thoroughly. Never plant deeper than the level at which your plant or tree was growing before. It is not necessary to do anything else until summer besides watering thoroughly once or twice a week as needed; do not over water, especially in cold regions. In spring and early summer you can prune lightly once again to encourage more bushy growth.