Moving existing lilacs allows you to remodel your landscape or save those that are inconveniently located. Some considerations when moving established lilacs are age, size and health.
In general, shrubs tolerate a move better than trees, while deciduous plants do better than evergreens. Younger plants tolerate transplanting better than older plants.
It is recommended to move trees and shrubs during the dormant season, according to Jeff Iles, Iowa State Extension horticulturist. Early fall transplanting works because lilacs can regrow roots without supporting top growth.
Plants with shallow and fibrous roots have an easier time than those with larger and fewer roots, according to Don Janssen, Extension educator for the University of Nebraska. Lilacs have fibrous root systems that help them get established after transplanting.
Transplanting damages feeder roots your lilac uses to absorb water and soil nutrients. This causes shock that can stop recovery after replanting. Plan for fall transplanting by root pruning in early spring.
Lilacs are deciduous, meaning they drop their leaves in the autumn. When this happens, it is your signal to transplant the lilac. Transplanting too late will rob your lilac of time to develop new feeder roots before winter freezes set in.