We're getting lots of unsightly weeds growing up among the rip-rap on our dam. All on dry land. Question: Would it be okay to use Roundup to kill them, trying hard to keep the Roundup out of the water?

I'm thinking to wait until rain passes.

Thoughts about this idea?

It would be better to use a glyphosate formulation approved for aquatic use, like Rodeo. Some of the formulation ingredients in RoundUp are hard on aquatic animals. I assume that you want to kill all the plants and not just broadleaves?

We use roundup twice around our pond in the rip rap to the lawn edge every year. I use it under our pine trees as well. If you don't shoot the new growth with the roundup it will not effect the trees.

Cheers Don.

It is like RAH says, it would be better to use a glyphosate (active ingredient in Roundup) product formulated specifically for use around water. The glyphosate is not the problem as I understand it, but the carrier used. The specific formulas for use around water are a little more expensive but not that much so.

I have done it but won't recommend it to others.

Does Rodeo have no surfactant or a different surfactant?

I assume not (or at least not enough) from the label:

"Use of this product without surfactant will result in reduced herbicide performance."

http://ws.greenbook.net/Docs/Label/L68194.pdf

If you think it needs some or more surfactant original dawn liquid soap will work. That is all soap is anyways. I do not know if that is harmful to aquatic life, I have not read that so check if you wanted to use it, but it will work. Maybe that would allow you to use rodeo, instead of roundup or eraser or the like.

Folks spend their lives doing research on such things and the label is based on this research. If you want the best effectiveness and safety, just follow the label. It just also happens to be the law as well. The label for the herbicide and surfactant will tell you what to use and how to use it.

Corn syrup is a fantastic surfactant. Best time to spray is in the early morning or late evening with dew. When the dew is on small plants open their pores to pull in the water. If you spray then they will pull in the spray that much better and activate that much faster.

It helps the most when it is really dry and late summer.

A surfactant will let the spray spread out on the leaf and not let the spray bead up on the leaf of the plant.

Cheers Don.

DonoBBD, interesting using corn syrup. I have used dish soap on my fields prior. How much corn syrup would you recommend in a 25 gallon sprayer? With dish soap I've really only used a few drops in the tank as to not foam when spraying.

You can also increase glyphosate's effectiveness by adding a little ammonium sulfate (a common nitrogen fertilizer) to the mix.

Brook, that makes sense and sounds like it would help jump the process...good idea.

For those that want to know more:

http://www.herbicide-adjuvants.com/cgi-b...ds=View+Records

I use on big glob in a two gallon sprayer. Its easier to dissolve it in a mason jar then pour it in.

The ammonium sulfate (spray grade of a fertilizer) is a water conditioner. So if you use it, you add it to the water before the glyphosate or any surfactants.

Glyphosate (active ingredient in Roundup) is degraded very badly by hard water. The various minerals in the water tie up the glyphosate very rapidly. In fact there have been some studies that have shown that using distilled water made Roundup work significantly better than lesser quality water.

So having clean water is important for Roundup type products. Of course for homeowner use where the amounts are rather small, simply using the upper end of the rate will offset some of the chemical tie-up. It may be easier and simpler just to use a little more glyphos than go to the trouble of mixing the fertilizer. But when spraying on a commercial scale we always add a water conditioner before using any glyphosate (either Roundup or generic) product. It just makes sense to have the product be as effective as it can for a given rate of application.

There are liquid products made specifically to condition spray water that are a lot handier than using ammonium sulfate (a granular fertilizer that has to be dissolved in the water). We have pretty much gotten away from using the fertilizer and have went to the liquid formulations, although the cost per acre is slightly higher. But no need to worry about agitation and getting the fertilizer dissolved so it will do its job.

More than most probably wanted to know.

So how close to the banks would you change from Roundup to Rodeo?

From section 5.3 of the label, it looks like 15 meters.

http://roundup.ca/_uploads/documents/RT540_label_Mar2014.pdf

You want to be sure it does not drift of wash into the water.

Thanks RAH.

Aquatic plants like waterleaf can easily be 30' to 40' away from the pond bank during droughts, and that's why I asked. My waterleaf is one of those nuisance plants that doesn't always play by the rules.

I hand spray with a little 2 gallon sprayer. Mix Ag concentrate at about four ounces in the 2 gallons. I spray right from the waters edge to the grass edge twice a year with no problems. Floating island and lily pads were not effected from any over spray or run off. I really think if I even just dumped the four ounces into the pond it would not kill any weeds other than the ones right next or around the spill.

The scary part of roundup transorb is the dihydrogen monoxide or DHMO. This crap is really really bad for every living thing.

That DHMO is pretty scary!

http://www.dhmo.org/facts.html

Something tells me the state highway departments may be in violation of that requirement at times.

I typically look elsewhere for a role model:)