Hey guys. I have a 5 acre lake that we dug last summer and because there is not a high amount of runoff, it is slowly filling and is currently only about a third full. By my estimates, it may be two more years until it is full or even above the rock line. We have a ton of weeds that are growing in the bank and I'm wondering if we should spray that with roundup or if it will die on it's own when the water covers them. There are already plenty of rills in the banks from where the water has caused some erosion but the rocks sit inside of a pretty good shelf so I haven't been concerned about that.

My wife wants me to kill the weeds because she is concerned they will continue to grow underwater and we will have weeds around the shore underwater. But then I started thinking that maybe it would be better to leave them to prevent further erosion. So I thought I'd get opinions from some others who have a lot more knowledge on this topic than myself.

For the most part, weeds that grow with air above their soil WILL NOT grow when submerged with water above their soil.

Personally, I would prefer to leave the weeds as erosion control for the time you finally get a frog strangler rain that runs hard into your pond.

Good luck on your new pond and finally getting sufficient rains to get it filled!

Turf is better than weeds, and weeds are better than dirt. I wouldn't kill them out until a more permanent option is ready to take over. Not sure what that would be in your area, but a state Ag office would be a good start.

I agree with FireIsHot.

Maybe add some groundcover that attracts deer or supports some other goal for your property.

Plant a few small plots and see what does well, and then fill in larger portions with the winner.

P.S. On a project like that, I would have my wife pick some (or all) of the plants. I have noticed far more support for my "projects" when she has significant input! Also, two heads are better than one.

Thanks for the feedback. So how would I plant grass without killing the weeds and tilling the dirt? With the existing slope of the lake shore below the rocks, I'm not sure how it would be possible to seed anything.

There are a lot of "small" seed groundcovers (like clover) that you can broadcast seed. I think your results would be much better if you raked a little on wet soil (prior to broadcasting) to get some of the seeds into the ground.

I would experiment with a few strips to see what worked for your conditions. Even some narrow strips of ground vegetation that run perpendicular to the slope of your shorelines would give you some significant reduction in erosion while waiting for the pond to fill.

I am certainly not an expert on this topic. Surprisingly, some of the people on the forum that make small food plots for deer might be your best resource!

I would kill willow trees and just leave the rest. My 1.1 acre pond was predicted to fill the first winter, but filled up over a 2 day period just 2 weeks after it was completed due to a record rain, and the emergency spillway got tested as well. Nice to have it fill, but that water must have added a lot of silt . Glad that it did not come during construction!

RAH adds a good point. There are some plants (mostly undesirable tree species) that can grow in soil under air, and can still grow in soil under water.

Much easier to eliminate any undesirable species like that, BEFORE the pond is full!

Just random stuff, but yes, kill the willows. I use Tordon on the cut trunks, but there are cheaper methods.

At this point, I would personally only treat the broadleaf weeds above the shoreline with a 2 4-D like Weedar 64, and leave the rest alone. It's rated for land and water, so runoff should not be an issue. Broadleaf plants usually create shade, and shade would keep any seeds you may plant from growing. Something to consider is that algae will probably grow when the terrestrial plants below the shoreline are submerged, and start to decay. On a 5 acre pond, I wouldn't think it was a major issue, but it is a consideration.

I believe Tordon is restricted from use below the high-water mark. A wipe with an aquatic-approved glyphosate formulation with the "glove of death" works very well. You can Google "glove of death". Be sure to use a rubber glove that is impenetrable by pesticides and herbicides.

I am pretty sure that the usage instructions for the "glove of death" mandate that you wear a hooded black robe and carry a scythe when treating weeds in that manner!

Glad that you are wearing the proper PPE:)

Yeah, I can't argue that.

Sounds like the general conclusion is to leave the weeds. So how can I easily determine if there are willows in the weeds? The weeds are pretty thick.

It would take a team of 10 men a week to rake all the dirt on the banks to allow me to plant anything.

I figured that would be the case!

Maybe just a few narrow strips of plants where some erosion is starting to show?

If not, then the existing weeds are probably good enough.

I'll check to see if there are places that could benefit from additional coverage. Thanks for the feedback. Will the existing weeds just die as they are submerged?

Yes they will unless they are willows or something growing in there, which is highly doubtful because its liable to be hard clay with very little moisture or nutrient load. , and even those will not survive in too deep of water and are pretty easily killed if they do make it. If it were mine, on the weeds, if you had a way to brush-hog it really high, like 6" to 8" high, you could utilize the tops of the weeds as erosion control ground cover, held in place by the base of the plants, either way they will only be there till water covers them up

One buddy had great success planting Switchgrass then mowing the weeds over it and allowing the mowed weeds become "mulch" to help keep the soil moist and another has had good success doing that same planting method in his deer clover plots. He overseeds winter wheat and just broadcasts the seeds, then mows the clover to about 2". I would think that method would also work with grass seeds.

I would leave the weeds as structure for your bait fish....