Pond Boss Forums AQUATIC VEGETATION Identifying plants Sago or Horned Pondweed or Widgeon Grass?

I have a 5 foot wide ring around my main pond of what I think is Sago Pondweed. It's blowing up, and don't know if I am blessed or if it's something I should try to manage. I'm not interested in allowing my BG fry any more structure to escape predation, but understand it's great for invertabrates including my grass shrimp.

I'd say 20% of my pond has now developed a thick ring of this aquatic vegetation. Should I let it be or take steps to manage it? Need your advice and also verification on what kind of plant this is:

Is it considered in poor taste to "bump" ones own thread?

I've done it, so probably.

It is my learned opinion that you have a rare case of South African Worm Grass. This is a highly invasive plant that must be controlled immediately by treating your pond with large quantities of Grey Poupon Dijon Mustard.

And you should only "bump your own thread" when no one is looking.

What type of "Pondweed" it is isn't that pertinent if you decide to treat it. I may be wrong but it appears all the pondweeds in the potomogeton genus are treated with the same herbicides.

How about selectively treating some of it vs. all of it and seeing if it gets more invasive later?

A quick search in San Diego public records will reveal JHAP did a little time for this very activity. Sicko.

Okay, thanks Cecil - good input. I know this is a rookie question, but can one get too much pondweed, even though it's considered a beneficial plant? Should I just be leaving it alone? Guess it all depends on my goals, and how much $$ I want to throw at the issue?

Hence the warning.

Without even knowing what it is, not sure on that, what problems is it causing? Is it expanding or do you think it has peaked? If you were to start eradicating it what means are you considering? Sometimes the safest bet is to let it be. However I just picked up a pond that is totally infested with Coontail. Let it be is not an option. And If I were to answer my own questions I would say...

It makes the pond unfishable and really unsightly.

It is expanding and is getting worse every season.

I going mechanical, or actually manual here by hand pulling and raking out. The less segment leftover the better, and it really does not have a root system. Just part of the plant is anchored in mud/sediment.

I think one more consideration is where did it come from? If it is just going to reintroduce itself that should influence your battle plan. My situation is it hitchhiked in on a fish delivery, not me. I took care of it on a larger 5 acre pond downstream but this is the source.

Yes you can get too much! I had Sago Pondweed pretty much taking over my biggest pond last year. It was growing up from the bottom in up to 11 feet of water to near the surface! In this aerial photo the light areas are all Sago Pondweed. This year I am adding more Aquashade, and once I can afford it some Whitecap (Sonar).

Came from fish stocking of Bruce's ponds he was so kind to provide me free of charge - of this I'm certain, I have zero in my other three ponds and have stocked none of Bruce's fish/pond water there.

I could manually remove, but there's a lot and it seems to be spreading.

Thanks Cecil...so, you just let it go last year? Am I late to consider aquashade? Seems a far more economical solution.

I've read about a lot of different chemical treatments for the pondweed. Anyone have suggestions on the most effective, something that could also be used on FA, and is the most affordable? Sorry for all the questions...jeesh, just when I thought I was beginning to master some knowledge I'm served a major curve ball! THANKS in advance guys.

See what you get when you bump your own thread?

We have people using the lake mower on sago on lakes 25 acres and bigger. The stuff cuts very easily and floats to the surface for collection. Mechanical removal is nice if you want to keep some for habitat but you don't want it to overtake your b.o.w.

TJ -- something is not quite right here. In my limited plant experience, I was pretty sure that sago pondweed only grows out to about 3 ft of depth. However, maybe that's because we usually find it in turbid waters.

I sent your pictures to our aquatic botany professor over in the biology department. Once he id's it for certain, I'll let you know what he says.

I have had a pretty solid algae bloom all spring - not too thick, just a healthy light green, and I thought that would block some of the sunlight penetration - so this explosion of pondweed has me surprised. I have a few areas that are growing out 8-10 feet from shore in water easily 6-8' depth. In other areas it remains pretty close to shore, as I expected it to. I really appreciate your willingness to help me out here...thanks Dave and all!

TJ -- I heard back from Gary Larson, our great plant systematicist.

I sent images 8 and 9, and he said "it was a good thing we had the close-up. Image 9 is horned pondweed (Zannichellia palustris). You can see a few of the small banana-shaped axillary fruits near the first joint of the middle finger."

He also spotted a second plant in Image 8. "There might be something else in the upper left of the distance shot floating on the surface with very long sheathing leaves. That could be widgeon grass, Ruppia cirrhosa, though there’s not much of it.

Um....is that good, bad, or the same? Widgeon grass and horned pondweed...any management recommendations?

Hey, I'm just in the identification business. Just wanted you to have the right plant (horned pondweed) as you chased your solution. Neither Gary nor I have herbicide experience. Let's see what our experienced plant control forum-folks have to say about this plant, and how best to control.

Thanks Dave...it's good to know what I have. I appreciate your help.

Talked to Grimes - said Reward will crush it. I may just do some spot treatments and consider stocking GC as a more permanent solution. I really should have been paying attention better, but any stocking rate suggestions on a 4 acre BOW? 10/acre suffice?

My grass carp experience say 10/acre will strip it in 2 years. Probably not much visible effect this year, or maybe even next year. Darn grass carp and that "all or none" syndrome. Sure wish we could get partial control, but other than one scientific paper documenting partial control, it tends to be all or none. I think I've commonly heard similar thoughts from other folks on the Forum.

I wonder if Crayfish could be a better option - feeding my SMB, YP and HSB while grazing on the pondweed?

TJ,

Once the plants are up Aquashade is too late. I removed my Sago mechanically with a weedcutter last year and it came back later. It was so much work i didn't want to do it again. This year I've applied the Aquashade early and at a higher than recommended amount. I'm not seeing any Sago Pondweed YET except possibly some in less than a foot of water. But I'm still going to apply the sonar once I get it. For the size of my pond I figure it's actually cheaper than applying any other herbicides more than once.

I won't add grass carp because:

1.) The DNR has made it a PITA to get them and the delivery cost more than the fish! (I'm not allowed to pick them up even as a fish farmer unless I resell!)

2.) The last ones I had took to the fish pellets!

What about Crayfish? Think they would make a dent?

Cecil -- our SDSU plant expert did say that sago grows up in at least 10-12 feet of water. He confirmed that it is a common plant in western plains states, and does well in water with clay turbidity, but only grows to 2-3 foot depth in that situation.