Glyphosate, the active ingredient in Roundup, is a good choice for a total kill herbicide. It is non-selective and will kill broadleaf plants as well as grasses. There are a few weeds which are fairly resistant, but this will get the large majority of them. This chemical needs to be applied when weeds are actively growing, so if it hot and dry, it would be a waste of money to spray now. Spring is best but some weeds grow in the fall also and are susceptible then. There are generics that are cheaper than roundup but have the same formulation. I use one called Eraser.

FYI - If this ditch carries any water flow, removal of the vegetation could destabilize it causing the sides to slump in. Also, moving water can carry the herbicide off site and impact someone else's plants.

Thanks so much for the info, botanybob. I wouldn't start spraying until, probably, January or February, when the weeds are 1" to 2" tall.

I don't believe the runoff would be a problem, as it just flows into a very long, dry-all-summer creekbed (I'm in rural foothills, well away from any cities). Of course, it eventually reaches a river, but I think it would be well diluted by then. If this still sounds like a concern, I'd like to hear that, too. I don't want to cause problems for anyone else. Thanks.....

It should not be a concern, as this particular herbicide adheres tightly to soil particles and generally does not present a runoff problem. This, along with its low toxicity and biodegradability, are reasons it is used in sensitive habitat areas for weed control.

Thanks so much to both for the info! Much appreciated :)

If you leave bare dirt the dirt will wash away. I am not certain that the law is Federal or just state by state but you must control your run off. This is why you now see barrior's such as straw bales and landscape fabric at most construction sites. Even though you are rural how much land do you own? What does your the next person down stream do with their property. Although RU does adhere to the soil particles you plan on washing those away by not having a ground cover. If your neighbors use the creek as a wet season water source you could be causing all kinds of problems.

I do appreciate your concerns, maifleur. You make some valid points. However, in my situation, I think it's OK. This normally dry creek (only has water during heavy winter rains) does not flow through anything for many miles which affects anybody's pastures, flowers, or anything else. I've followed it for miles just in taking walks, and there's just nothing there. By the time there's enough water in it to flow, it is so much water that the little bit I'm putting in will be well-diluted. As for runoff, I guess I didn't make it too clear in my original post. My driveway is about 100 ft. long, with small drainage ditches on each side. There is no concern about them collapsing, as they are only about two feet deep at the deepest part (most of it is shallower). By the time it runs off, there is MUCH water flowing everywhere, and even if they do produce some runoff, it will be so diluted that I don't see it as a problem. Still, I really do appreciate you taking the time to respond and voice your concerns. If, after what I've told you there are still concerns, I would definitely like to hear them. That's why I'm posting now, before the weed season hits. I want to do it right, and I do sincerely appreciate the input here.

Best to all....mystified_grower

Thank you for your posting my concern was with a wet weather creek the people down stream might be using the water to irrigate some early crops. I was not concerned with the collasping of your ditches but unprotected ditches tend to develop small gullies which as time goes by get bigger and bigger. The top of the gully could undermine your driveway in a couple of years. If you do denude the ditches watch them for erosion. You may have to put rock in the ditches in future years. Another thing to think of is before you spray tell your neighbors and spray on a non windy day. I have some friends that received spray drift from an uphill neighbor that did not realize the spray would fly that far. I understand that he repaid them for the plant stock they lost but loseing three growing years hurt them. The mental hurt of not knowing what was killing their plants and worry about the children getting sick really bothered them. Enough of my soapbox. Take care and be safe.