While lilacs can be a burden to move, depending on their size, it is possible to move one, just be sure to have help on hand for digging and heavy lifting. Lilacs prefer full sun and well-draining soil, especially on a slope. Before you move your lilac, make certain the new location will be a permanent one, with soil similar to the soil in which the plant has been growing.
Dig the area around the lilac by starting a foot away from the base of the plant and digging all the way around in a circle. Dig toward the plant, 1 1/2 feet deep.
Work toward the plant until you are able to put the shovel under the lilac and the bush is no longer anchored in the ground. Place the head of the shovel firmly under the root ball of the bush.
Have your helper grip the base of the bush and pull the lilac up while you use the shovel as a lever, pushing the handle of the shovel down to lift the root ball up.
Take the lilac to its new location and dig a hole 6 inches larger in depth and width than the size of the root ball. Set the lilac bush in the hole, and fill in any gaps with garden soil or compost.
Water the lilac well to fully saturate the soil. Continue to water deeply whenever the soil is dry until the vigorous growth of the lilac begins again in a few weeks.
Spread mulch around the base of the bush in a large circle 3 inches deep.