Answer: Lilacs tend to show swelling of their buds well before they actually leaf out. I would expect the plant to show some signs of life by now even if it is partially shaded and thus a little behind the other plant. You could begin at the top of the plant and look for life by trimming away the stems bit by bit until you reach some with green on the interior, indicating it is still alive. The plant can regrow from a relatively small amount of wood. (It can also regrow from the roots, although if grafted the new plant from the roots would not match the old plant.)If it is still alive, you might consider transplanting it to a better location with full sun. I'm sorry about your lilac.
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