How to Prune Spiral Evergreens. Sculptured topiaries lend elegance and an air of cultivation to a yard or garden. Evergreen trees are particularly suitable for this type of pruning. An experienced pruner can create fanciful shapes such as animals and people, while the home gardener can create simple shapes, such as squares, spheres and spirals with minimal skill and experience. It is easiest to create a spiral evergreen from a cone-shaped tree.
Tie one end of the twine to the very top of the trunk of the evergreen. Double-knot the twine and pull tightly so it does not come loose while you are pruning.
Walk around the tree slowly. As you walk, tie a knot onto each branch that you wish to prune. Do not pull too tightly -- the branches should not be pulled toward each other, but should remain in the same place they were before the application of the twine. Wrap the twine around the tree in this fashion until you reach the bottom branches.
Examine the tree. Visualize the tree with the twined branches removed. If the spiral shape of the twine is not to your liking, adjust it so only the branches you wish to remove are tied.
Cut the branches marked with twine as close to the trunk as possible. Work slowly from the top of the tree down. When all the branches are removed, cut any remaining twine away from the tree. Trim any ragged edges so the spiral design is clear; you may need to remove the branches on the sides of the spiral design you have outlined, especially if your tree's branches are very close together.