Glyphosate (Round Up) is pretty safe as far as herbicides go, but I would look into safer alternatives. If there isn't a pasture of weeds, think about manually pulling them with a weed hound (linked below, $20 Home Depot). You can also use high strength vinegar as a non-selective weed killer.

Glyphosate is readily broken down by soil microbes but I don't know if the same is true for the weeds you just killed (or even if your puppy likes munching on those).

Here is a link that might be useful: Weed Hound

Hi eriocaulon,

Thanks for responding to my question. I'm going to give the vinegar a shot and see how it works. Also, while I was at the store buying a spray bottle for the vinegar, I came across a dog repellent made by LiquidFence. Say's it all natural and safe for family and pets. Maybe try using this around the flower beds to keep the pup out all together. Anyone have any luck with repellents?

Thanks,
Brad

Here is a link that might be useful: Dog repellent

I have only tried Liquid Fence deer repellant and it works well. Sometimes I forget to apply it again--seems to last 2 weeks at most. In any case, that product sounds like it's legit.

you can also just pour boiling water on the weeds.

i use RU all the time around my house, several hundred gallons a year, but then again my dog rarely eats the weeds too.

Vinegar only works on hot, sunny days, so plan your attack.

The Weed Hound is a great tool. It makes pulling weeds very easy.

The standard "household" vinegar is marginal at killing weeds (and I'm a proponent of vinegar). Like Eriocaulon said, search out the high-strength vinegar to kill weeds.

Thanks for the replies. I found some vinegar at Lowes that said it was 20% (as compared to the stuff we have at home which is 5%). Perhaps I'll give that a try. It's suppose to be sunny and near 80 today, so it's probably a good day to apply it.

I'll also give the Weed Hound a try. There's a Home Depot nearby which is moving locations and they're having a clearance sale so I'll run by during lunch and see if I can snag a deal.

Thanks,
Brad

Unless chemically treated, anything that will kill a weed will kill other green matter including a lawn.
The broadleafed weed killers, chemistry has made it safe to use around naturally growing grass.
But it still is poison. Dogs only have to walk on the area of the spray to be affected. Like squirrels and cats, they wash their faces with their paws..

Do the dogs regularly chew on foliage outside. If not, there's not much danger if they were to smell RoundUp.
Spraying vinegar will keep the little guy away from planted areas and generally no harm to any extent grass it might land on. But why not spray something else and lay that in the area.

Spraying 20% vinegar will keep EVERYTHING away for 20 minutes or so. One of the reasons this strength of vinegar is not considered much of a hazard is the fumes will knock you down before you get too close to it.

BUT IT IS A HAZARD. If you use it be absolutely sure you don't accidentally spray it so the wind blows it into your face. It can burn your eyes such that it takes months to recover (from what I've read).