No definite conclusions as of yet, but something is definitely happening to the lilac branches I am attempting to propagate.
These pictures were taken on day 10 after preparing the branches and planting them (see earlier post: Propagating A Lilac Bush). Not sure what the white specs are all over the stems, but they don’t rub off.
Another note: Since planting the stems in the pot of dirt, watering it, covering it, and storing it in the greenhouse, I haven’t yet had to water it. The moisture that builds up under that plastic bag is keeping the soil more than moist enough.
I can’t wait to see if this experiment in propagation works. For now I’ll take these little specs of white as a hopeful sign, and for this I am — Simply Grateful.
Simply Grateful Housewife 
Can you let me know how your lilac propigation worked out
Sorry for the very long delay in responding. This comment got lost. Unfortunately the lilac propagation was a bust. The branches I used dried up and never rooted. Next year I’m going to try something different and hopefully I’ll get a different result.