A forest of suckers has replaced my departed Lombardy poplar. Should I just keep pulling the suckers, or would a chemical treatment work better?
Susan Witt, Potter Valley, CA
To get rid of suckers, use a paint brush to carefully apply herbicides to only the undesirable trees and shrubs.
Photo/Illustration: Jennifer Blume
Dan Dalton, arborist at Glen Gate Company in Wilton, Connecticut, replies: Lombardy poplars (Populus nigra ‘Italica’) are notorious for spreading by root suckers after the main tree is removed. The remaining root buds become active in the spring when the tree comes out of dormancy, resulting in an abundance of unwelcome suckers.
You could spend the rest of your life either pulling the suckers out by hand or chopping them back, or you could go the easier route and kill what’s left of the tree with a glyphosate-based product like Roundup. This chemical is one of safest to use in the home garden, but it is a non-selective herbicide. It will kill any plant it comes in contact with, so special care should be taken when applying to keep it away from plants you don’t want harmed, and be sure to read the label before using. An added benefit of glyphosate is that it has a short residual life, which means that it doesn’t stay active in the soil for long.
To apply it, paint or spray the exposed stump and suckers with a 50:50 solution of glyphosate to water. Another option is to spray the foliage of the uncut sprouts with a 1:10 solution of glyphosate to water. If the suckers are very large, cut them down to the ground and allow them to resprout to half the original size before spraying. This will reduce damage to nearby desirable plants from drifting spray. Repeat the process as needed until suckers no longer appear.