Waterhemp - disaster

[nwmn]

So I live on the river and have this 2 acre area that was all reed canary grass and canadian thistle last year. I sprayed milestone on the thistle patches and gly on the reed canary. Success. This spring no reed canary or thistle was anywhere. I winter sowed native species and this spring walked it and spread even more seed after snow melt so the threat of seed runoff was low.

I got back from a work trip and noticed a blanket of green throughout the entire bottom. Pigweed was everywhere. I sprayed with gly early thinking I could get ahead of the issue before the natives germinated and were canopied. Fast forward, waterhemp laughed at the gly and now it's a thick blanket of waterhemp that I've been mowing 3 times this summer before it is able to set seed. I'm not totally in favor of letting the seed mature as I will be sitting on billions of seeds if I let it go. Of course, I spent a lot of money on plugs at a native nursery and planted a few areas of wetland species that are doing alright as I hand weeded the areas earlier this summer. The time I've spent hand weeding pigweed, lambsquarters and waterhemp I could have spent doing productive things.

I'm at a point now where I'm considering two options.

1. Spray the entire area minus my 'gardens' with milestone and making the river bottom free, for the majority of the area, of weeds.
2. Disk the weeds and eliminate via mechanical means. With this approach I would need to get in and plant smothering crops like winter rye, oats, buckwheat etc to keep any new garbage from taking over. This may also get the seed I threw down this spring to get better soil contact.

What other options are there? Keep mowing? This is rough on my mower as I run my zero turn over it and skid steer when it gets really tall. I know If I mow it, it will still find a way to produce seed as these plants are the devil and will branch out. Leave it? I don't want more weed seed on the property so I really dont want to do this. Disking it may be best, but getting the tractor stuck would be a disaster, however there has been limited rain.

 

[Hoytvectrix]

That is a really tough one. I was in a somewhat similar position a few years ago. I was only trying to establish switch though, so my options were a little easier. I thought I had everything killed from a few applications of glyphosate. Smartweed started to bounce back and show up better than before. I thought I had wasted all of the switch seed and time with the drill. I ended up using two applications of triclopyr and took care of the smartweed in that area. Anything that is coming up still I have decided to just leave it.

I think smartweed is invasive enough that you are likely to have a lot of weed seed in the soil. I think I would try and control what you can now, and then hope the natives will be able to out-compete the smartweed seedlings in the future. I think a lot depends on how much you have been having come up so far for knowing what to do. Smartweed isn't all that competitive once the cover gets above a foot or two. You will see it, but I don't really ever find patches of it like you might with reed canary grass. The area I planted (about 4 acres worth) is about as ideal habitat for smartweed as possible, and I don't really see it taking over.

I'd be curious to see what others think. Definitely a tricky situation.

 

[nwmn]

Smart weed is definitely in there as well, but the main foes for me is waterhemp and yellow foxtail.

I'm so tired of battling weeds. I've got cost share assistance to manage common tansy as it's considered invasive in our county. I had to spray beautiful areas of milkweed and parts of my switchgrass as the tansy is incredibly thick in areas. Canadian thistle and tansy likes to inhabit the same areas as common milkweed which makes it super difficult to manage without guilt lol.

I'm hoping to be able to burn this fall and apply gly over many areas this fall once beneficials are dormant. I think it's a multi year process so I'm hoping to get the garbage under control so I'm not harming the good stuff when it's more prevalent

 

[Hoytvectrix]

Well I'm an idiot that apparently lacks reading comprehension.

 

[nwmn]

Lol, no worries. All these weeds seem to inhabit the same areas.

 

[Ben.MN/WI]

24d kills waterhemp, but it also kills most other broadleaf plants at the same time. Even if you kill off the patches of waterhemp, that will create an opening that will allow a new flush of plants to take off. And there will likely be a large number of new waterhemp seedlings just waiting to take off. Could you kill everything off, plant straight switch grass (which I believe you can spray with 24D, but i'm not 100% sure on that)? You could then spray the switch grass with 24D to kill off the waterhemp and after a year or two the switchgrass should choke out any waterhemp seedlings.

We see a lot of waterhemp around here on soybean and corn field edges, but I've never seen it in established CRP, alfalfa road ditches and other areas with established sod.

 

[Brokenbear]

Any time you till the ground you are digging into new weed "seed bank"
So my playbook would say no till or broadcast cover seeds
Determine if your water hemp, pig weed/smart weed have become "gly" resistant which it sounds like it possibly has ..if after you sprayed your sprayed area was not dead black brown for the most part but was sickly yellow/green then you have resistant weeds
We had to change to the Liberty Link spray for that very reason and it makes the field black as an eight ball (vegetation wise) ..however it is NOT a strong performer on grasses and often it is recommended that "Cleth" be used along with the Liberty herbicide to kill grass ..it is also a good idea to use a surfactant or at a minimum 1oz of plain old liquid dish soap per 25gal of water but put the soap in the very last and stir slightly
It is possible but with no guarantees that you can over spray where your native are and only set them back and not kill them but of course a test area sprayed with the Liberty Link spray (generic name Interline) Coop $104 2.5gal 3oz/gal mix rate (boom sprayer) quart to the acre

Bear

 

[nwmn]

I've had great luck with glufosinate so far(knock on wood). I went ahead and sprayed the yellow foxtail with clethodim yesterday, as it has been choking out my milkweed colonies. I also mixed in milestone after spraying grasses and covered my waterhemp areas good. Hoping they curl up by the weekend and will continue to keep them at bay. Next step is to broadcast winter rye throughout the entire area and see if I can choke anything trying to come back. My goal in this area is to convert to natives, and I know aminopyralid is one of the safer herbicides to use in natural areas. My vision is to have a meadow full of swamp milkweed, joe pye weed, ironweed, and many other lowland species that can grow tall and put out all sorts of color.

Waterhemp certainly doesn't provide that, and robs everything else of moisture and sunlight. Fix one problem(reed canary) and open the door for 3 more problems to combat. Any time I've made disturbance I've been inundated with noxious plants. This scares me away from wanting to do any logging as that sunlight will almost certainly create a thistle nightmare and would be tough to manage with aspen stumps and resprouts everywhere. I've got a 3.5 acre area I just sprayed, burnt, and now disked and plan to direct seed acorns into this fall. I bought a gallon of clopyralid, so I plan to let the weeds grow, and hit them with some of that prior to broadcasting oaks. Should keep thistles at bay and doesn't damage the oaks.

Part of the journey is learning from mistakes, and the one mistake that I keep making is weed management prior to planting permanent cover. Winter rye and oats will be used in every restoration effort going forward.

 

[Angus 1895]

I would offer considering using synergy.

2,4 D opens up the plant’s ability to absorb other toxins.

surfactants may also help.

 

[S.T.Fanatic]

Keep mowing through the first frost in your area. I would not mow lower than 12" however because what you want to grow may not be able to overcome being mowed so short. I would thing that would be impossible with a zero turn. Once a frost or two have taken out the warm season stuff I would hit it with a good application of gly to take care of the rest. We did over 40 acres years back and it was to much to take on all at once so it didn't turn out as good as we would have liked but It pretty decent. We mowed several times the first year about half as many the second year and probably only one time the third year. Those natives spend most of their time putting down roots so you need to be patient.

 

[Brian662]

I've had good luck planting Enlist (or equivalent) soybeans for a couple years and nuking weeds. May consider beans with a winter cover of rye/med red clover to choke weeds on second year. Not sure how your lowland area would respond to a bean planting though.

 

[SD51555]

Stop spraying.

That is opening up an already charged seed bank that will keep throwing stuff at you until you go crazy. When everything above ground is dead, the organic acid profile of the soil changes and that activates all those super weed seeds. They were always there, they were just resisting germination until the right conditions presented.

Most super weeds cannot compete in healthy soil. What they are adept at is thriving in dead soil because they are a unique plant group that doesn’t need mycorrhizal fungi (the backbone of healthy soil) to usher nutrients into themselves.

I’d take a step back and ponder whether you’re trying too bend nature too far. Far as where you’re at right now, I’d keep it mowed short and mow it until first frost. If you can find someone to work it up, I’d work it up late and just plant rye, 2 bushels/ac.

Beings that you’ve sprayed Milestone this year, you won’t get any broadleaves or legumes to go with your rye. Let the rye go as far into August next year as you can, and then throw and mow more rye, and a cocktail of perennials from the other plant groups. It’s not gonna be perfect, but that’s about the best path forward that I see.


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