Pond Boss Forums AQUATIC VEGETATION Controlling unwanted plants American Pondweed

I have a posted reply in the ID plants forum but I figured I was asking the question in the wrong forum so I appologize.

Anyway, I have a problem with American Pondweed. The plant was anywhere from 10-60 feet out along the entire shoreline of my 8+ acre pond.

I have been treating it with Weedtrine. This seems to be working but up till today I thought the plant was Water Shield. After I mentioned this, I was told that weedtrine wasn't actually doing much of anything and I should maybe try Renovate.

After researching and coming to the conclusion that this isn't water shield, now I wonder if that same advice still applies?

It certainly seems to be killing and sinking this plant but I'd like to know what's happening since this stuff is somewhat expensive.

On the Missouri dept. of conservation's website they call the plant diquat what does this mean in relation to the herbicide? Just wondering because that same term was used when talking about weedtrine.

Diquat is the active ingredient in Reward or Weedtrine

This contact herbicide is effective at burning back pondweed, but it will grow back. I think Reward is more concentrated than Weedtrine.

Perhaps Kelly will pipe in with his usual sage advice.

Sage advice?

Anyway.... REWARD and WEEDTRINE D share the same active-ingredient (a.i.) - called diquat dibromide. However, REWARD's formulation contains 2 lbs. of a.i. per gal. of product, while WEEDTRINE D contains only .4 lbs. of a.i. per gal.

So, REWARD is basically 5x the concentration of WEEDTRINE D, and usually only 2-3 times the price per gallon. Therefore, if one has enough treatment-needs to justify two+ gallons of WEEDTRINE D, it would be a better value to simply purchase REWARD.

Regardless of the name on the diquat container, it still won't provide much more than a topical burn-back effect on most rooted plants.

So then what do you suggest would be the best plan to get rid of it? Aside from what I've been doing. Is there a better chemical to handle it?

The proper answer is a little more complicated than simply determining which product to use. It also depends on your pond's design characteristics, whether there are desirable species also present and, most importantly, your well thought-out objectives.

Personally, I would want to retain some types and/or levels of vegetation in a fishing pond. But, some pond designs tend to allow too much vegetative coverage - thereby requiring some intervention to keep it in check. This to simply say: sometimes a plant problem may be avoided, or maintained at optimum levels, by constructing or renovating the pond's perimeter with steeper slopes (increasing the water's depth beyond the comfort zone of many plant species).

IF this option isn't possible, and IF herbicides are deemed appropriate, and IF there are no water-use issues to be considered: I'd probably look into the use of AQUATHOL for controlling areas of American pondweed. It is usually very effective on this specie, and treatments may often be isolated to targeted areas/shorelines - offering better access there, without controlling the entire plant population in the pond.

Of course, if you want to control all of the American pondweed (and several other plant species), SONAR might be a spring time consideration - provided that your pond doesn't experience frequent or significant flow-throughs during typical rain events.

Did that answer your question, or simply muddy the water even more? Sorry, if it was the later. But, there are no cookie-cutter answers for the wide variety of situations and objectives that pertain to aquatic vegetation management.

I am familiar with a lot of common names for species in the "pondweed family". Can't find this one. Anyone know the scientific name for American pondweed so I can look it up?

I will add another "wrench" or idea for weed management in ponds. I conclude that smaller bodies of water are often fished too hard or harvested too heavily or improperly. Excessive weed growth can limit or reduce the amount of fishing pressure a water body receives and the fish get a respet or "break" during the weedy season. In a few cases like this excesive weed growth may actually benefit the overall fishery. Fisherman quickly get discouraged when havieng to contend with lots of weeds and look for other easier to fish places.
Just a thought.

Bill - you're right. I can't find a single reference to that name.

But, I vividly recall seeing American Pondweed (somewhere) listed as Potamogeton americanis.

Is my fragile memory confusing it with something else?
Potamogeton species

P. nodosus? Does that help?

Basically, I have about 100 yards of shoreline that I want NO plant growth. I don't mind a little pondweed around the rest of the perimeter but it is so aggressive, it's hard to stop it going everywhere. It was literally 60 feet off shore in several places.

There's a small strip of willow trees that are quite mature and it seem to provide alot of fish cover. That's where I catch the most anyway.

Renovating this pond/lake's bank is not an option, oddly enough, most of it is relatively steep as is.

Water-use is limited only to livestock consumption. Flow-through, not sure what you mean by that I guess. But if you mean basically overflow after rain then it does quite a bit of that.

There are, from what I can see, no other species of plant on probably 90% of the lake. There's some algae in a few shallow areas and that's about it.

I don't have a problem with over harvesting my fish pop. There's only about a dozen people who fish here and the lake is >8 acres. Some of these guys just catch and release too so it's not a big concern.

Potamogeton nodosus is called long-leaf pond weed and American pondweed in Water Plants for Missouri Ponds. I planted that "suff" in my pond. So far I don't have it taking over. One man's good habitat is another man's weed problem, we all have different objectives, goals or uses for our ponds.

Gleeser - 1. How deep does it grow in your pond? Clearer water will allow it to grow deeper. The book says it grows up to 4 ft deep, but rarely do any of these plants read those books. In my pond it so far grows to abt 5 ft deep in my clearer water.

2. Is it growing well in muddy-mucky or sandy bottom?.

I like the plant becaue it makes great fish cover but it is difficult to fish a lure through it. I fish the edges. I would kill it the same way you kill water lilies. If possible just treat the areas you want to kill. If you leave some of it you will discover that more fish will hang out in this area. Denude it and the fish will go somewhere else. The underwater parts (stems & leaves) in a "bed" or patch harbor millions of invertebrate critters that serve as fish food buffets for minnows, bgill, etc. Over 500 "bugs" were found on just one plant in WI.

AQUATHOL K (liquid formulation) has some water-use restrictions (fish-consumption: 3 days, livestock watering: 14 days, etc).

AQUATHOL SUPER K granules also lists various restrictions, but doesn't specifically site livestock. I've asked the mfgr for clarification, as omission doesn't always constitute permission. Label> AQUATHOL SUPER K Label .

The impact of this product is usually confined to the treatment area, although some diffusion (impact) may be observed in untreated adacent areas. Treatments should be conducted when two consecutive calm/sunny days are anticipated.

I guess my memory was off on the P. americanis name - but I sure thought I had seen it somewhere in the past. ** I just noticed that the label linked above lists "AMERICAN PONDWEED" as P. nodosus. So, there's a bit of confirmation for you. **

Planted it??? Man, I can't imagine that! Like you said though, "one man's habitat..."

It grows at least 5 feet deep I'd say, haven't measured it. And, it grows in muddy bottom water. It seems to be the thinest around the willow trees, maybe because of less sun?

The water here is quite clear.

Aquathol, from what your saying Kelly, doesn't sound like a great option for me. I say this only because of livestock restrictions you mentioned. 14 days would be virtually impossible as it feeds about 700 head of cattle 90% of the year. But in a lake the size of this one, the ppm would be quite low I'd think.

Does this Aquathol "stay put" pretty much? I mean, say I treated an area 150 feet from the water pipe, for example. Do I still need to keep livestock off this water for 14 days?

I think I'll have it handled this year but I'm sure it'll be back next year. Definately going to hit it earlier. That was what lead me to my question about aeration over in that forum. Hoping to possibly slow this mess down next season.

Gleeser - I not only planted them, I paid money for them!

I would also consider using some white amur to help control it or in conjunction with chemical treatments. I lent out my white amur books and they have not been returned so I cannot look up the taste preference rating of this plant to amur. I will try and get my references back soon. Knowing a little about the plant I would think amur would relish P. nodosus and it would not take too many fish per acre to thin the plant in your "pond". However if your luck is like mine the fish would eat the plants in other areas first rather than the targeted areas.

AQUATHOL SUPER K (a granular formulation) DOES NOT reference a livestock water-use restriction (see the linked label: under "environmental precautions").

Only the AQUATHOL K (the liquid formulation) does list a water-use restriction for livestock. Why the two product formulations list different restrictions is puzzling.

The SUPER K granules settle directly within the treatment area. However, the active ingredient is soon released from the granules and may move laterally if currents are present. That is why one should only treat when calm days are expected (preferably two in a row).

Well, it's been nearly 2 years since this problem started and still no results with any treatment I use.

I stocked either 40 or 80 (have to check but I think 40) Grass Carp last year and they have done virtually nothing as of yet.

It held off till early May but then it really turned loose and you can nearly see the growth by the day.

That's some thick stuff, Gleeser. What treatments did you try other than the grass carp? Haven't seen Kelly post in a while...your problem looks like a real challenge. Is there a lot of fertility in the water? Is there significant run-off from nearby land that is highly fertilized? That may be the cause...fertilizer was the cause in my case.

If you stocked 40 grass carp in 8 acres, that isn't nearly enough for a problem of this magnitude. On a smaller scale, treating with Reward a couple of times in the year and following that up with young hungry grass carp finally worked for me on a bad pondweed invasion. The grass carp prefer new growth and won't touch old growth if there is anything else to eat. So, killing it back some and then letting the grass carp loose on the new growth, worked for me....but now I have too many grass carp in the effected pond!

Yeah, I'd say there's signifigant runoff from farm ground. Roughly 300 acres worth likely all treated with fertilizer. To describe the runoff I get, this 8.6 acre lake filled completely up in 2 days. Granted it was a very high amount of rain, somewhere around 12" but nonetheless that's alot of runoff.

I started with round-up, followed that with copper sulfate granules, followed that with a chemical I can't recall the name of, followed that with weedtrine D, followed that with Grass Carp... etc.

There is no raking this stuff out. I worked on it for a couple hours one night in one spot and barely made a dent. It was totally covered back the next day. Good excercise in futility.

I am completely at a loss. On top of that I know squat about managing a pond. This lake is close to 20 years old and has never experienced this stuff except for the last 2-3 years. The shoreline is massive so these non-working chemical treatments are really eating my pocketbook. I'm open to anything that will actually work.

We live in Mid-Missouri and I just discovered this site for info on American pondweed control. We have a 3/4 acre pond and in the last 2 years have pondweed taking over. It extends out approx. 8'. It is just now emerging since spring is in the air. What should we do to begin the demise of this? Should we start the treatment just as it is emerging again for the season or should be wait until it is up really good? astubbs

Now this is an old thread brought back to life!

I'm not an expert. I can't give you control measures. Others will be along shortly that can help you. But I can give you some things to think about in your process of getting rid of an unwanted weed.

The weed is there for a reason. There are unused nutrients it is taking advantage of.

If you kill it, some other natural process will take advantage of the nutrients the pond weed is now using. It might be more or even less desirable to what you have now. Just something to keep in mind.

For example, if the pond weed is eradicated, the nutrients might create a huge algae bloom. That could be great for the fish, but your pond might turn a completely different shade of green than it is now and suddenly no longer be as clear as it is (if it is clear now). The pondweed might be replaced by some other weed that the birds bring in. I don't know how many different weeds grow in a pond, but it is a high number. Something will try to use the nutrients available. You might end up with something much less desirable as what you have now.

Man, I'm sounding like a downer. Don't mean to sound that way, just wanting you to be able to "think ahead" in that once you get this weed eliminated or at least under better control, it might introduce other issues. Having thought about the potential ahead of time can allow you to plan better instead of jumping from the fire into the frying pan, so to speak.

Hope this helps. The ones who actually know what they are talking about will be along shortly.