Q • My lilac bush stood in a foot of water for a week during our recent flood. The leaves all turned brown and shriveled. After the ground dried I placed a ring of compost around it. Is there anything else I can do to possibly save it? Would pruning help?
A • The flood was certainly an unfortunate event, but you’ve done all a gardener can for now. If the roots are still alive, the shrub will eventually push out new growth. That could be in the weeks ahead, but it might not be until next spring.
In the meantime, I would recommend not doing any pruning at all at this time. Otherwise, you might cut off live wood that is critical for the shrub’s survival. Live growth will be flexible and pliant, and if you lightly scratch the bark near the tips of branches, you should find green cambium tissue present. Dead branches and twigs will be brittle and snap when bent, and the cambium tissue just beneath the bark will be dry and brown.
Re-evaluate your lilac next spring once all chance of frost is past in mid-April. By then, you’ll know what’s live and what’s dead, and whether the shrub made it.
Write to Chip Tynan of the Missouri Botanical Garden at firstname.lastname@example.org or Horticultural Answer Service, 4344 Shaw Boulevard, St. Louis, 63110.