It should be safe. It's my understanding that Roundup works on green growth. I think the active ingrediant is "glyptosomething or other" and is no longer patented. Look for something with the same ingrediant for about half the price.

It'll need a couple of hours before watering or rain to work.

Glyphosate - active ingredient in Round Up. It starts to degrade and become inactive once in contact with the soil. You will want to coat the foliage of the target plants so they absorb it. It is useless to spray it on the ground between the plants (should not affect tree roots below the soil surface).

If a little spray strays onto the bark of the oak, it shouldn't affect it as long as there are no little branches/leaves at that point. Point here is you can spray right up to the tree, play it safe and don't actually spray the tree, but don't worry if there is a little drift onto the bark. If you should get any on leaves of the tree, remove the leaves immediately before it can soak in.

If you're spraying around a bush or small tree, a nice piece of cardboard as a shield helps.

Glyphosate-the active ingredient in Roundup and its' generic equivalents-is absorbed through green plant tissue. Thus, a little bit drifting onto old, dead outer tree bark will cause no problems. One caution relates to spraying on very warm, humid days. Under these conditions, small fissures in the old, outer bark can open slightly, leaving inner, live green tissue exposed. Any glyphosate that reaches these surfaces would be absorbed into the tree. But, you would have to really be dousing the tree with spray to reach the level where damage would be done.

Also, be aware that all species of plants are not alike in terms of their susceptibility to this herbicide. Elms, for example, are though to be especially vulnerable to its' effects.

But in general, as long as you keep the spray off the landscape plants, no harm should come to them. As others have already said, no activity in the soil.

+oM

Yes, I've got Roundup Extended Control and Roundup with a guaranteed 10 minute kill if it were to rain that soon after an application.

The directions on the extended control state that ordinary "non-extended-control" should be used on plantings less than 6 months old. The directions also state to use cardboard as a barrier. The extended control will be your best option for older trees.

Dax

i use it in my hosta beds with 2000 hosta and hundreds of trees... with no problems .... as long as you dont hit what you want to live.. you will be fine...

now lets talk about the INSTRUCTIONS ....

roundup/generic credit are not approved for application by bucket ... i know you were PROBABLY using your terms lightly ... but PROPER APPLICATION requires reading and use.. according to the instructions ...

so get a pump tank ... read the instructions.. and most important... remember it isnt perfume... practice with plain water on the driveway .. and learn to adjust the nozzle and the amount of pressure.. to develop DROPLETs.. which will fall to the ground.. too much pressure.. and it will be drifting everywhere ...

use a hose to outline the bed.. spray into the bed ... and then cover with mulch .. you will be all set ..

and use the proper amount for killing grass ...its only an ounce or two per gallon .. not a bucket of roundup to two buckets of water ...

with droplets.. you wont need the cardboard.. i tried that once.. the cardboard gets wet and drops drop everywhere you dont want them ...

just remember ... dont walk across the sprayed part for a day or two.. or in a few weeks you will have mysterious footprints all over the good grass...

i use credit EXTRA.. the extra is a surfacant ... to help spread the goo ... it is rainproof in one hour ... as i believe they all are ... you will know.. IF YOU READ THE INSTRUCTIONS >....

one other thing.. if you have stressed the grass to near dormancy .... it might seem like the killer is not working .... because the grass is dormant .... you might actually want to water it a few days in advance.. to get it growing again ... so the killer will work faster ...

good luck

ken

Whitcomb, Establishment and Maintenance of Landscape Plants (1987 edition, revised 1991, Lacebark Inc., Stillwater) describes two episodes of what would appear to have been root-absorbed Roundup. In both instances the trees damaged were oaks. There was no leaf or stem contact. There were growths of weed species that produce substantial roots present on both plots.

Since roots of all plants are growing in the aerated soil near the surface, perhaps the Roundup could have been translocated from the foliage of both weed species into the soil and after the death and decomposition of the weeds, the chemical was absorbed by roots of the trees...

The likelihood of this happening seems remote, yet the trees were dead only in the areas where nutsedge and milkweed were treated with Roundup. At this point additional caution appears justified when using Roundup on perennial weeds with extensive roots or storage organs near woody landscape plants