Last year I noticed a neglected lilac in the middle of a thicket of volunteer trees in my daughter's overgrown yard. The house was a repo and the we are just now getting the yard under control. Anyway, the lilac produced the most lovely light blue flowers. This year I decided to get a sideshoot from the bush or to make some cuttings.
So far have only taken the cuttings. I removed a branch and threw it in the back of the pickup and drove three hours home on the very warm day. Got home and forgot about the branch until the next day. At that point, placed peat moss in a deep contain, cut the branch up into short four or five in pieces, leaving only a leaf or two on the top portion. Dipped the twigs into rooting hormone, placed them in the peat moss, and covered the container with clear plastic.
So far the results are unbelievable. Every twig, 100%, has new green growth and seems to be doing well. If I can get these cuttings to survive, it will still require some luck, as my daughter is about 120 miles north of us in N.C., zone 7. So the likelihood of this lilac growing and blooming is a long shot. Still am excited about the early success.
If nothing else, this would seem to indicate to me that lilacs cuttings are very easy to root in the spring time.