Every year I dig out at least ten bush honeysuckle seedlings that the birds or wind have dropped into my garden.
If you have a larger infestation with bigger plants there are a couple of options which I have researched.
An expert in the field recommends that home owners use Roundup as a first round of defense. If your infestation is bad you can try Garlon, same as Triclopyr, which he uses at the Shaw Nature Reserve. He says that you need to follow the label recommendations. (note – this article says that Garlon is not effective. ARTICLE)
MDC recommends a 20% solution of Roundup.
Doug D, an arborist, recommends a 50% solution of Roundup and water. He uses an old fashioned oil can to put roundup on the stump that you cut.
Curse of the Bush Honeysuckles is a good PDF article. It recommends, “Application should occur in late summer, early fall or the dormant season. Spring applications are less effective on stumps because resources are flowing to new buds instead of the roots.
I have found that the same chemical can be found in Ortho Brush-b-gon Poison Ivy Poison Oak, & Brush Killer.
Another chemical is NOT recommended – Tordon. My expert friend says, “I don’t recommend tordon because it stays active in the soil for a long time (sterilizes the soil for up to a year) and it is taken up by tree roots from the soil, killing non-target tree species.”
I hope this helps you with your battle with bush honeysuckle.