My Transplanted Lilac Needs Help

I have a relatively large lilac that was transplanted (to the right of the Arborvitae in the photo). I had a bunch of different ones that I was trying to transplant and unfortunately they stayed out of the ground a little too long and most of the lilacs didn't come back, but this is one of the few that did. However, it only has leaves on the tops and a few new ones at the base. It is making all of the branches sag and droop being so top-heavy. It was transplanted about 2 1/2 years ago and it did get a few blooms this year and it's all done blooming for the Spring. Should I trim it back? If so, how short should I go? (for perspective, it is next to a 4 foot fence so the Lilac is probably about 6-7 feet tall)

Help!

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Steph
www.FetchDesigns.com

I would prune it back, probably next spring after it finishes blooming. Never cut off more than 1/3 of the living part of a plant in one season. You can, however, remove all dead branches. Pruning the top will not only help give it a nicer shape, it will help encourage new growth from the bottom, giving it a fuller look.

Here are some links that might have some helpful information for you:

http://web.extension.uiuc.edu/cook/news/news13119.html

http://www.gardenersnet.com/lilac/lilac02.htm