Experts and BHG readers answer.
Possible vegetation killing spray on my 1 yr old Lilac bush.
Unfortunately, once the plant absorbs the herbicide, there's not much you can do but wait and see. It's possible that the lilac didn't absorb enough herbicide to completely kill it. You may notice a defoliation followed by releafing. Entire branches may be killed, but the crown may survive and send up new shoots. If you'd witnessed the spraying, you could've grabbed the hose and washed it off quickly to avoid damage.