Lilac trees (Syringa vulgaris) are attractive garden favorites with smooth green leaves and fragrant blooms. The most common bloom color, as the trees' name suggests, is soft purple, but pink and white varieties are also available. These hardy trees do not protest excessively when you find it necessary to transplant them. Reduce the negative impact of transplantation by taking into account the lilac's preferred growing conditions and moving the tree in spring or fall.
Select a new planting site that receives at least six hours of sun a day and contains well-drained soil. Prepare the new planting location by digging a hole large enough to allow the roots to spread out when replanted. The size of the hole depends on the size of the tree to be transplanted. Larger bushes generally have larger root systems.
Amend the planting hole with 3 to 4 inches of organic compost.
Dig a circle around and under the lilac tree, beginning 2 to 4 feet from the base of the tree. Be cautious when digging to avoid damaging the roots, which can be quite extensive. Remove the tree from the ground.
Shake the roots to remove any dirt still clinging to them. Spread the roots out as much as possible when placing them into the planting hole. Replace the soil a little at a time, patting it down as you go to prevent air pockets.
Water the tree gently to avoid disturbing the roots until the soil feels very moist. Continue to water the newly planted lilac tree whenever there is less than 1 inch of rainfall per week until the first hard freeze of the season.