Lilacs sprouting from roots

[LibbyLieu]

We planted lilacs in the areas between our basement window wells. In the last 2 years, the lilacs have become agressive and are sprouting from the roots and penetrating the weedblock or finding their way to the edges of the weedblock. I have cut the sprouts back but that seems to make them more agressive. What can I do, short of cutting down the main lilac bush and replacing it, to stop the continued sprouting from the roots of this bush or at least to keep it under control?

[IntrepidMeredith]

Unfortunately, many varieties of lilacs do spread via suckering, and the common lilac (Syringa vulgaris) can be especially aggressive about this. My best recommendation is that you dig out your lilacs (replant them someplace where they can spread, or find a group to donate them to), and replant the area with something that doesn't sucker. Among lilacs, if that's what you want to stick to, I believe that Persian lilacs (Syringa x persica) would be a good non-suckering choice. Ditto the Chinese lilac (Syringa x chinensis 'Saugeana'). Ask at your local nursery for the best recommendations on non-suckering shrubs for your area.