Round Up works on disrupting photosynthesis. With no leaf there's no photosynthesis. I've been told that Round Up photo degrades within 24 hours.

What does seem to be effective is to let the tree push new buds next spring. Let them grow for a while, longer than a few weeks, then apply Round Up. Repeat as necessary. It works best on actively growing plants.

If the leaves are still green, it might work. But the active growing time - spring and early summer - is best.

will it work on a stump after leaf fall? Nope ... and it won't be there next spring. The only way to use it on a stuymp is to apply it to the freshly cut surface of the stump of an actively growing tree.

I've used RU (glyphosate) on freshly cut stumps after leaf fall and have still obtained reasonably good results, but the concentrate should be used at 50-100%, and it should be applied immediately after cutting (preferably on a relatively warm day). There does seem to be some variation in effectiveness depending on species.

application is 100% full strength ... so really 41% .. applied with the tech heavy applicator at the link ...

i am not stopping ... leaves are still green.. and days are in the low 70s ... no time to lose ....

ken

Here is a link that might be useful: link

Kill kill kill, eh Ken ?
I have some young trees that managed to sneak past me...thought I got them all, but gonna wait till next spring for more sure kill vs try now.

FWIW, basal bark applications can be made right through early winter. Now that's not exactly what you're talking about, but it does give some indication of how long this sap draw-down goes. And I should say too, basal bark apps are typically a Garlon-type herbicide, that is, one with the active ingredient triclopyr, not glyphosate. Additionally, a fuel oil (or equivalent) carrier is the recommended way to apply this class of herbicides. This too allows for better efficacy in sub-freezing temps.

+oM

>Round Up works on disrupting photosynthesis.

It does not directly disrupt photosynthesis, it directly blocks the synthesis of a class of amino acids (aromatic amino acids). Of course, once the plant is dead, photosynthesis has been "disrupted" in a manner of speaking :)

Fall (when trees are going dormant) may be the most effective of all times for this type of treatment. I've had excellent results from applications made as leaves are dropping and shortly thereafter...even on normally-hard-to-kill stuff.