Pond Boss Forums Thread Like Summary - Pondweed

Should i kill off the pond weed that is quickly taking over or leave it to let my recent addition of CNBG have a place to hide?

That depends on what type of herbicide you use, how it's applied, and at what strength. Granular herbicides are easier to use to spot treat, but you can also subsurface inject with liquid herbicides. It also depends on the weed that you are treating too. Some are more susceptible to certain kinds of herbicides than others. That's why proper weed ID is important.

One does not have have to get into the pond and get wet to manually get the weeds cut. I don't get wet to remove those types of cut floating vegetation out of my pond when you have the right tools. The floating cut weeds and wind moves the weeds to the shoreline where they can be easily removed with a rake. Dead sinking weeds contributes more to the depth of the bottom muck. Someday you will need to drain the pond and get all that deep bottom muck scooped/sucked out. Put that on your future capital appropriations list.

I would only kill it off in the areas that you want to fish.

American Pondweed aka long leaf pond weed. Amer. pond weed is great pond plant and great habitat for fish as long as it does not cover more than 25%-30% of the pond shallow water areas (littoral zone).
How big is the pond???
As esshup says granular herbicide is good for spot treating some areas to kill back the pondweed so it is not so abundant to initially and quickly open some areas to fish.
If it were mine, I would this Spring add a low number of grass carp (white amur) to eat some of it and thin it out - reduce it - so not as much is present. Initially GC are slow to get it noticeably reduced the first year. GC are MUCH easier to add than remove!!. A good benefit of using GC instead of chemicals is they eat it to produce manure to feed the good phytoplankton and zooplankton community to create more plankton turbidity to help NATURALLY shade out the deeper growing pondweed. Go slow with adding extra GC as they need to be 1.5 - 2.5 yrs old to see their affects on effectively reducing the pondweed. I think 3 or 4 GC per acre can eat at least 3-5 pickup truck loads of Am pond weed per year converting it to plankton fertility depending on size of the GC. Ideally you don't want pondweed growing deeper than 6-7ft.

Pond dye can help reduce the depth that the pondweed grows. Remember you really DO want some pond weed present - due to its numerous benefits. Use according to label or slightly less. I would first start with blue dye then later blend in some black with the blue. Black dye is mostly blue with some red and yellow added to get the darker black shade.

I think the best way to start with your Amer. pond weed infestation is a good combination approach. Use some granular herbicide early in the program for some quick partial weed reduction, add an appropriate few GC, add some pond dye. ALL depending on the size of the pond, Initially for the first year, manually removing some of the pondweed is also a very good idea. Less chemical to mess with, give the GC time to eat and grow, dye shades the deeper growing weed, and ALSO manually removing some gives you good exercise, garden mulch and pond activity observing the status of the pond. Manual removal will better educate you on the extent of the problem so you see the success progress over the next few years. A Lake Rake with rope and a Weed Razor are very good tools for manual weed removal methods to have in the Pond Tool Box.

Again how big is the pond?
How deep is it? and
How clear is the water? Amer.pondweed tends to make the water clearer so it can grow deeper.
REMEMBER you always want some Amer pondweed to compete against Filamentous Algae and you have fewer problems with FA.. Actually the more pondweed you have the Happier the Water Quality is for growing fish.

There's a tutorial in the archives I believe. You first have to post them on an on-kine image hosting site. I use Imgur. I have APW in my in my pond and the leaves aren't much over 3"-4" long at adult size, they start out about 1/2" long.

I'd hit it with a low dose of Fluridone (@ 7-10 PPB). NOW before it has a chance to set seeds which it will do towards the end of June. That low of a dose will only kill that and any Eurasian Water Milfoil in the pond and not affect the other plants in the pond. The fluridone takes 30-45 days to work, so there is no need to worry about an O2 crash.

esshup is giving accurate info. I would treat asap - the earlier the better. If it were mine I would definitely do as esshup says and importantly knock it out before it has a chance to set seeds by evidence of seed/flower heads at the surface and turtions at leaf axils. CLP is a pest and there are a lot better submerged weeds for a pond than curlyleaf. If you use a brand of Diquat (examples Harvester or Reward) it will knock it out plus other plants quickly before it reaches the surface.
I use Diquat to control my CLP. If you do not aerate the pond with bottom diffuser the Diquat may not be mixed to the bottom zone and will not kill the CLP in the deepest water. Thus regrowth happens again next year. The diquat when applied has to mix into all the CLP stems/leaves especially into the deepest growing plants or diquat does not contact and kill them. Diquat does not last more than a few days unlike Floridone (Sonar) that lasts 40-60 days. If you bottom aerate then what you apply the circulation currents will mix the diquat throughout all the pond depths. According to label 1 gal of Harvester will treat your 1/2 acre with average pond depth 7-8ft.