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Using Round-Up

Posted by GGardens 8 (My Page) on
Mon, Mar 4, 13 at 16:32

Has anyone used Round-Up to contol weeds? Yesterday I sprayed Round-Up on some very weedy beds where I want to transplant/add some roses, hydrangeas and other plants--how long should I wait before tilling and planting?


Follow-Up Postings:

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RE: Using Round-Up

Read the label.


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RE: Using Round-Up

Thank you, jean001a however the label did not provide the info I was really looking for. From other's experience, I'd like to know how successful have their results been using Round-Up. Was a reapplication required? There has been some rain after I applied the Round-Up and the weeds still look the same. Any advice beyond the label?


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RE: Using Round-Up

GGardens, you aren't giving us much info. Are the weeds that you sprayed actively growing? Are leaves visible? Roundup works through leaves.

Did you spray well before it rained? Roundup needs a few hours of dry weather to be absorbed.

Did you make the concentration that the label recommends? Or was it the premixed stuff?

In general, Roundup works much more slowly in Winter than it does in Summer. Figure several weeks.

Are you in the Pacific Northwest? If so, I don't think you should be tilling until around late May. The soil is too wet. For digging and planting, I would wait several weeks after applying Roundup. A couple of reasons: you will be able to tell if the weeds are dying, because they will turn yellow; and Roundup may not deactivate quickly in cold winter soil. So I would recommend patience.

The reason people are reluctant to give advice is because they don't know your level of skill, they don't know if you followed directions, and they don't know if you did something completely unpredictable. So it's always good to give as much info as possible.


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RE: Using Round-Up

I had Shotweed growing like crazy in my gravel driveway (good luck hand digging it out!!), we had a warm day on the weekend recently probably mid-50s, I sprayed it with Roundup, there was no rain for about 18 hours after I sprayed it, a week later the Shotweed is completely dead. I'm actually amazed it worked because the night temps were really low and mid-50s sounds really questionable for Roundup to work but luckily it did. I live in a suburb of Tacoma, WA. The shotweed was pretty small when I sprayed it, perhaps that's why I had good results vs. if the Shotweed had been more mature perhaps it wouldn't have worked.


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RE: Using Round-Up

I live on the Olympic Pennisula; I'm about 2 blocks from Liberty Bay in Poulsbo, WA. I have moderate experience gardening--mostly failures. So in trying to reburbish my small garden, I thought I would seek expert advice. I used the pre-mixed Round-Up last Fri when it was in the mid 50's, there was no rain until Mon nite--only night moisture. I'm trying to get rid of dandelions, English Ivy creeping over from the neighbors, grass, some sort of weed that looks like fuzzy shamrock with many but short roots and a weed that sticks like glue to your gloves when you pull it.


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RE: Using Round-Up

I should have mentioned I used concentrate and put it in a 3 gallon garden sprayer and also include "Spreader Sticker" sold by McLendons to get the solution to stick to weeds. I started using this when I was trying to kill some ivy and salal since both have slick leaves and solution would just run right off.


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RE: Using Round-Up

The Roundup will kill the dandelions and grass,but it won't kill the English ivy. With a plant that's growing from somebody else's yard, you need to be careful, because Roundup is systemic, and will eventually kill the entire plant. But as I said, you can't kill English ivy with Roundup, unless you really work at it.

Here is a link that might be useful: English ivy control


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RE: Using Round-Up

Disagree re: not being able to kill English Ivy with roundup, I've done it but at the end you do state it takes persistence, that part is correct. I worked at it a whole summer and it is now gone.


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RE: Using Round-Up

  • Posted by bboy USDA 8 Sunset 5 WA (My Page) on
    Tue, Mar 5, 13 at 23:23

You probably could have made fall applications to the ivy and gotten the same outcome, the summer applications were perhaps wasted.


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RE: Using Round-Up

bboy: WRONG! everyone knows English Ivy is VERY difficult to kill so your comment is clearly WRONG.


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RE: Using Round-Up

bboy, what's the reason that the Fall application is better? Is it understood, or more of an experimental finding?


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RE: Using Round-Up

  • Posted by bboy USDA 8 Sunset 5 WA (My Page) on
    Wed, Mar 6, 13 at 12:22

Fall applications of glyphosate tend to be recommended for woody plants, blackberries for instance. In this case they are transporting chemicals from the top to the crown (bud head) at that time of year, glyphosate applied then is thought to be concentrated in the overwintering buds in the crown, resulting in more damage than during the growing season.

Ivy, of course is not a cane grower with a bud head, but will still be growing less actively in fall than in summer. I don't know what, if anything the label or other source of direction says about ivy.

Recently a landscape contractor friend and I were discussing using glyphosate to kill giant morning glory (Calystegia). As I remember it the directions say to begin applications when flowering commences, the idea being that at that time the top is now big enough to take up enough herbicide to kill the roots - this is a recurring theme with glyphosate application. He pooh poohed this, saying that he did not get good results with morning glory until switching from summer to fall applications. Starting at flowering time was a waste of time and money.

At $100/gallon for the super concentrate (at CostCo prices), I definitely would not want to be trying to clear out a patch of ivy with repeated growing season applications if it was possible that was not the most effective time to be making them.

This post was edited by bboy on Wed, Mar 6, 13 at 12:27


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RE: Using Round-Up

  • Posted by botann z8 SEof Seattle (My Page) on
    Wed, Mar 6, 13 at 13:38

I have, and am, removing Ivy with Crossbow. It works way better than Roundup. Crossbow works better for Clover and Horsetail too.


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RE: Using Round-Up

Glyphosate (RoundUp) is most effective on plants in active growth - since it is translocated from the foliage to the root systems and then throughout the plant tissue, the foliage must be actively photosynthesizing to achieve this movement efficiently.

It is still a bit too early in the season for a lot of plants to be in active growth. Some early weeds perhaps but the vast majority need a few more weeks before your use of RoundUp is most effective. Generally, the recommendation is to apply, wait to see results (7-10 days) then reapply as necessary. If/when plants are in active growth, the results may be evident a lot faster - a day or two depending on species. The less active the growth, the longer for results and the less effective those results may be. The second application is more or less for insurance purposes :-) It is not always easy to tell at the time if your first application was thorough or complete.

As to the effectiveness of RoundUp or its generic equivilents on ivy, fleshy and glossy evergreen foliage - like English ivy - has a waxy covering or cuticle on the leaf that makes penetration of the herbicide into the plant tissue very difficult. There are additives you can get that helps with that process but that is the primary reason why the RoundUp/Rodeo/Ranger Pro type products are not recommended for ivy control. Crossbow is a different herbicide altogether and has a more far-reaching toxicity. It's overkill for most weeds.


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RE: Using Round-Up

Crossbow is great for controlling broadleaf weeds in lawns. But I've never tried it in cold weather. The label says it should be used in warm weather.

Crossbow is also systemic, so if you spray Ivy from your neighbor's yard, it may kill the whole plant.

Here is a link that might be useful: Crossbow


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RE: Using Round-Up

As far as Round Up sprayed areas being used for gardening, it does not poison soil. It works through the plants leaves.

Though it is still too early to work soil in the PNW.


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RE: Using Round-Up

Roundup is inactivated by soil bacteria. That doesn't work so well in cold, wet winter soil. I've killed dormant bulbs with Roundup applied in winter, even though they had no foliage. It might take a month or more for it to be inactivated. In the winter, that's plenty of time to get washed into the root zone and beyond. It pays to be cautious with this stuff.


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RE: Using Round-Up

I sprayed RU liberally around my fruit trees last summer and within 2 months 2 trees died. I discussed it with a local commercial farmer with a large orchard and he had the same problem. He said RU killed a lot of his peach trees, so now he limits the spray to 10 ft from the trunks of all his trees. He rototills around the trunks to control weeds.


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RE: Using Round-Up

  • Posted by bboy USDA 8 Sunset 5 WA (My Page) on
    Thu, Mar 21, 13 at 0:36

The Carl E. Whitcomb book Establishment and Maintenance of Landscape Plants has a chapter on glyphosate apparently affecting trees through their roots.


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RE: Using Round-Up

I respectfully disagree with the manufacturer's stated safety of Round-up and encourage those considering the use of it to do a search on the hidden dangers of Round-up. Natural News has an article with references.

Another important consideration is that monitoring by the US Geological Survey (USGS) has revealed that glyphosate and its breakdown product Aminomethylphosphonic acid (known as AMPA) are frequently found in rainfall and rivers in the Mississippi Basin, where most GM crops tolerant to glyphosate are grown.

Green Med Info site has an article on the health concerns of eating GMO foods with glyphosate residues

Thank you for allowing me to express another (evidenced-based) opinion.


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