I installed a rock bed around our pool 5 years ago and regularly coat grass killer all over the rocks because this stubborn grass keeps infiltrating it since year 2. I laid weed barrier, when I built it, but I think it is disintegrated because it stays wet during cold months. I even found some grass killer that kills grass for up to a year and used it all last year and it still gets in this rock bed. In February, I put a heavy amount of Prodiamine in there thinking it’d be so toxic it wouldn’t grow anything. I was wrong. Whatever this grass is, it dies and comes back within 2 weeks. Any ideas on how to stop it? I’m almost ready to give up and just cover the area with pine straw. It covers 1/3 of the pool on the left side, hardly any on the other..
by Qna15
7 Comments
Apply spring pre-emergents when the 5 day average soil temps are in the 50-55F range. Or use [this tracker](https://gddtracker.msu.edu/).
If you have a question about pre-emergents, read the entire label. If you still have a question, read the entire label again.
Pre-emergents are used to prevent the germination of specific weed seeds. They don’t kill existing weeds.
Most broadleaf weeds you see in the spring can’t be prevented with normal pre emergents. You’d need to apply a specialty broadleaf pre emergent in the FALL.
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You need roundup with the black label. It’s the 12 month one or whatever. It works very well when I’ve used it
Kill it with grass killer. Remove some rocks. Put down two layers of heavy duty landscaping fabric. Replace rock and buy some extra rock. Should be good.
RM43 Total Vegetation Killer
[RM43 ](https://www.domyown.com/rm43-43-glyphosate-plus-weed-preventer-p-20489.html)
It’ll work, i promise.
Prodiamine is designed to ***not*** kill grass, so that’s not the right product. Just use glyphosate once a week. The 365 stuff probably isn’t making it down to the soil and it doesn’t do anything sitting on the rocks or weed barrier. You could maybe poke a ton of holes in the barrier and apply the 365 stuff deep if doing it weekly isn’t your jam.
On stone? Fire.