You could cut out the brown parts, it seems like they're bothering you. Or you could wait for new growth to cover it up.

If the weeds are grasses, use Grass-b-gone, or some other grass specific herbicide.

Round-up doesn't work very well on ivy, you could try half strength on your weeds. It may leave brown spots on the ivy leaves, though. Get really close to the weed and try to hit just the weed. If the weeds are wild grape, Virginia creeper or poison ivy, half strengh Round-up won't cut it. They, like ivy, need several doses of Round-up, or 1 1/2 strengh, or Brush killer. Or hand digging.

I have a lot of English Ivey. During a long illness I let it go and it is now overgrown with Virginia Creeper. I tried pulling it out by hand but that is impossible. Can I spray it with something that wil kill the Creeper but not harm the Ivey? Thanks. Cecil Jones

I don't think there is anything that will kill creeper without killing the ivy. English ivy is usually considered a pest so all brush & vine killers target it.