Dear Members: > --not only do the plants have to be in active growth, but glyphosate must be administered to the foliage - it's ineffective if sprayed on the stem or roots! I once sprayed Roundup around a young oak, to kill some clumps of perennial grass. The leaves were not sprayed, but some spray did get on the stem. There was no damage to the oak that year, but the next year there were discolored and deformed leaves typical of spray injury. I've seen grape vines that had had grass under them killed by roundup. Again, the leaves of the grapes were not sprayed, but the canes were hit to a minor extent. The grapes were also damaged. A landscaper once told me that dawn redwood (Metasequoia) was damaged when the grass in the rootzone was sprayed. Didn't see it myself, but I don't spray around dawn redwood without taking extreme care. (Dawn redwood has shallow or surface roots). I know people who use a paintbrush to apply Roundup to the stems or root ends of woody shrubs/vines. Apparently it does work, even though it isn't being applied to foliage. There is a place for/need for weedkillers, but caution may be a good idea. Don't spray something you don't want to kill. Ken