Why would you need to wrap lilacs? Lilacs are extremely cold hardy. Generally any wrapping of plants for winter protection would be to preserve flower buds (hydrangeas), to prevent dessication on broadleaved evergreens or to provide some added protection on marginally hardy plant choices.

And you want to wait until after the first hard frost before wrapping deciduous shrubs - or once the leaves have fully wilted or dried and fallen off. Can't tell you about wrapping BLE shrubs as it is not needed in my climate.

define wrapping .... ken

I think the OP is referring back to the question about vole and rabbit proofing her shrubs using 'Dewitt Treewrap'. Tree wrapping

The wrap is intended to go around the trunk and perhaps the lower parts of main branches to protect against sun scald, trimmer injury, etc. Used in this way, it should have no effect on dormancy at all. It should not be wrapped around still green leaves or soft new growth.Encasing the entire shrub in tree wrap so it becomes a kind of horticultural mummy is probably a bad idea even if done when the lilacs are fully dormant.

define wrap ... and how you are thinking of doing it ...

in my MI ... very close to your zone ... if using stakes and burlap ... it sure wouldnt hurt to drive stakes now ... before the ground gets real hard ... and then wrapping in late nov ...

i think you are correct on thinking you should let them get real dormant ... naturally ... before you create some bizarre micro climate around the trees ...

frankly.. i still cant comprehend doing all this for lilacs .... or frankly.. any other shrub ... if they are strong enough to survive on their own.. who needs them ....

but i know you march to your own drummer.. so.. as always.. good luck....

ken