If weeds must be treated with herbicide, the chemical glyphosate (sold as Round-up and a number of different names) can be used on weeds that are actively growing. Use Glyphosate Properly to Protect Woody Plants. Re-planting can occur within four weeks after weed death. A: Because I see this so often, I believe it is glyphosate damage to your shrubs. Q: What do you know about recent findings that Roundup harms trees when sprayed under them to kill weeds? A: I found the article you read and reviewed it. So roundup may kill your tree but it didn’t kill my well-established elm trees. Hello, One of my over-anxious neighbors decided he was going to help me out and sprayed round up around ALL my flower beds. Q: Can plants other than roses get rose rosette disease? Hand-weeding and using a mulch over the area to prevent re-growth of weeds is a better strategy where replanting is desired. (A stray drop of vinegar on a desirable neighboring plant will cause some browning, but probably not kill it.) I have very established plants in all of them and don't use round up. ... are not affected by a particular herbicide. The use of glyphosate I find so important in Winter is against weeds that come from seed. Is there a safe way to use Roundup near trees? Often referred to by the uninformed as ‘annual weeds’ they are not exclusively so; they might be annuals, biennials or perennials, they are merely seedling weeds - or if your maintenance is poor they might be rather larger! When you spray Roundup on weeds, it settles on the leaves. I have nandina, geranium, boxwood, hibiscus, rhododendron and other plants that are showing symptoms of rosette disease. Rhododendron is difficult to treat chemically because the uptake of foliar-acting herbicides through the thick, waxy leaves is low. Environmental impact: As you might imagine, there are two camps on this. Yet, the question will roundup kill trees remain an interesting topic. But beware, because it is systemic, if a little drop gets onto another plant, Roundup will kill this too. I sent an email to … Field experiments have been established to examine the efficacy of a range of chemical herbicides applied as stump treatments to control regrowth of cut infected rhododendron plants. Since this first attempt to kill trees with roundup, I have done a lot of research on how to kill trees. Kill moss with an herbicide and it can easily be mowed or lifted out of your lawn. If you accidentally spray a small section of a plant you want to keep, the whole thing dies or only that section? Apply by spraying Roundup on the leaves of any plant you want to kill. Only a trace amount is involved because more than a trace would simply kill the shrubs. As long as the round up doesn't touch the leaves of the plants you want to keep, they will survive? Systematically, this is what you need to remove overgrown and unwanted weeds. Roundup is simply a product that primarily contains the ingredient glyphosate, which is clearly a chemical. He sprayed all around my Azalea & Rhododendron and under them. It’s strong and powerful to damage certain areas of plants from the leaves to the roots. Aided by surfactants in the chemical mixture, glyphosate permeates the leaves and enters the the plant tissue that transports food. How It Works. In my searching, I found a recipe from the Utah Ag Extension that uses roundup and will kill even the toughest trees. Killing perennial weeds is best done before planting with materials like 2,4D and Roundup which leave little or no soil residue.