Italian cypress looks more like a pillar or an obelisk than a tree, due to its tall, narrow growth. Some Italian cypress grow as tall as 60 feet, but may not grow any wider than 3 feet. Because of this, the tree lends itself to sculpting into narrow topiary shapes, such as cones or spirals. The cone is one of the simplest forms in which to trim an Italian cypress.
Choose a tree with an upright growing habit and a central stem. This type of tree is already roughly in the proper shape for a cone.
Rough cut the shape of the cone with a pair of long-handled shears. Your cuts do not have to be precise at this point, but avoid cutting too deeply into the tree. The interior portion of an Italian cypress's branches may have no foliage on them, due to shading from the outer portions. Avoid cutting the tree's limbs so deeply that this bare zone is visible. Step back from the tree to examine it after every few cuts to ensure that the tree looks correct.
Tie a piece of string to the central tip of the tree to act as a trimming guide. The string should be long enough to reach the ground while being pulled taut, but should not pull the tip of the tree off-center. Pull the string taught so that it forms the angle that you wish to trim the tree along. If the lower end of the string is closer to the trunk, the tree will form a thin cone. If the lower end of the string is further from the trunk, the tree will form a fat cone.
Hammer a stake into the ground at this point and tie the string to the stake. Measure the distance from the stake to the trunk of the tree. Whenever you move the string, make sure the stake is this same distance to the trunk of the tree.
Trim the tree along the line using a pair of hand shears. Once you have trimmed all the branches along one portion of the tree so it is level with the string, move it to a new place and trim the next section of the cone.
Pinch out the tips of the branches when you have finished so you remove any needles that have been trimmed in half. This will help you to give the tree a natural look. Leaving the needles in place will give the tree a sheared look.