Round Up just doesn't work

Over two weeks ago I sprayed two smallish areas with above recommended strength Round Up. I followed this up with two more mistings.

The results were very poor. One dandelion is looking a bit sickly, but other plants, including grasses, periwinkle, two shrubs have remained the same. In fact, some now look healthier!

I did some internet research and it was the general consensus that Round Up was slow to act, but this slow!

It's not cheap at over �£6 for a small bottle, but I had better results with a budget weed killer from Wilkinsons.

 

Yeah, so did I. That's why I use the Wilko's one now. :D

 

Roundup is slow Mike. But in most cases it does what it says on the tin (or bottle!). Give it at least three weeks before you despair as it can take quite some time to travel down to the roots.
In some cases if works better if you bruise the leaves before application.
I've found it works quite efficiently on grass but on bindweed I've found applying it with a fine rose on a watering can works better than a pressure sprayer.

 

It tends to depend on how quick the plants are growing. It works best , and quickest in spring when all the plants are growing extremely fast. At this time of year things will start to slow down in plant growth terms, there is no longer the rush to grow quick to get into flower. I would not yet right off its effects. I cannot understand why you used above recommended strength and why you used several applications unless you thought some was washed off by rain.
Roundup works best as a spray, when the dilution is higher than when watered on and you should wet the leaves but not so much that the droplets run off. Take up is best when the plants are in active growth and the soil damp.
Its good at killing weeds and grass but not shrubs. For those I would use a brushwood killer, though you might as well just dig them out cause you are going to have to dig the dead shrubs out anyway.
As to whether or not you use Round up it does not matter. The active ingredient is glyphosate and that is pretty reliable.

 

I agree with Geoff. Plants often look 'greener' after spraying with Glyphosate, but that is the chemical affecting the plant. I use it all the time. I have to say that buying the ready mixed, or small bottles of it can be a false econom, if you use it on a regular basis. I bought some concentrated at over �£30, but it has lasted into its 3rd year now.
Using it at a greater strength than recommended can actually be counter productive.
For glossy leaves plants you can add a little washing up liquid to the spray, it makes the water droplets stick to the plant long enough for the active ingredient to soak in.

 

Thanks for the advice everyone. Re the shrubs, does Round Up only work through leaves or is it also absorbed through stems and branches?

 

No, glysophtae is absorbed through the green leaves. That is why it may be used around bare stemmed trees.
Had another thought. One think you can do, perhps a little earlier in the year than this, is to chop everything you want to kill, down. Then, spray the new growth as it appears.

 

Have been reading this thread with interest, good idea Palustris

 

Glyphosate - the active ingredient - will kill pretty much anything. It does take a while to see visible results, though.

But don't bother buying a brand name like "Roundup". It's no better than a cheap own-brand one, or even a spray from the Pound Shop, as long as the active ingredient is the same.

 

I've found Roundup to be better than other glyphosate based products. The active ingredient is the same, but I think its something to do with the chemicals used to make it stick on.

However, I've never found it as effective as the label says. I find that many repeat sprayings are needed for particularly troublesome weeds.

Indeed, I once had cause to wage war on a bindweed infestation in my back garden. After the initial clearance, I did a daily 'bindweed patrol', carefully scrutinising the ground looking for the evil weed. Lots of new growth sprouted at first, but I'd put plastic tubes over it to isolate it, then spray it. I'd do this daily until the target was clearly dead.

 

I'm not a chemist or biologist, but just an ordinary person who care's enough about things to do a bit of research before I use chemicals for a particular job. Here's my understanding:

First up, glyphosate does have a bad side. It is harmful to aquatic life, so should never been used near or pond or stream. Nor should treat plant matter be allowed to contaminate the water.

Glyphosate biodegrades into starches and minerals that would normally be found in the soil anyway, but the process is driven by microbes that live naturally in the soil. Therefore I guess it could be retained in dead plant cells for a while, until those cells degrade so that the microbes can get to work on the glyphosate.

The more questionable thing about glyphosate based products is that glyphosate itself isn't much use. It would just run off the plants before being absorbed. To counter this, various other chemicals are added to make the spray foam and stick to the leaves. I found it much harder to find information on these additional chemicals.

 

Well FWIW I don't "suppose" on this.

I see lots of "Its bad" information on my travels around the internet, but anything that is not backed up with links to peer reviewed science I ignore; I have no idea what axe such authors may be grinding!, or whether they just heard it somewhere and are repeating it.

Its possible that Monsanto is big enough to suppress negative press about Glyphosate of course ...

Clueless1's point about the Surfactants is a good one - that might be a reason to use Roundup rather than other Generics as it has been around the longest, and thus more likley for any issues to have come to light than other formulations?

I just adopt an attitude of being careful. We don't put any chemicals on our veg patch at all (very occasionally insecticides, but I don't remember any in the last two years) ... but there again I don't know much about the provenance of the Manure we use