:blob2: Ortho Brush Killer works real good. However!!!!!!! I've used this product and it will kill thru the root system of any shrubs that are close by. So if there's nothing close by that you are worried about, it works very well.
I use a product called Savage . It contains 97 % 2,4-d in a dry soluble powder . It will fry any broadleaf that you spray it on and it is very cheap . If you use the liquid form of 2,4-d it can become volatile with high temps and harm other plants . I have never killed a non target plant with savage .
If there is desireable turf in the area of the fence, a Roundup application will take out the grass also. Using a selective like triclopyr (AI in Ortho Brush-B-Gon and other brands) will allow you to control the target pest and not hurt the lawn.
I have used triclopyr for 15 years, and have never seen root absorption by non-target woody plants. And I have often treated woody weed plants underneath desireable ornamentals.
The ideal for vines like posion ivy is a mix. Round-up will knock it back, but often not kill it permanently. triclopyr is the key for this. You can use a straight triclopyr or if you only have confront or something, use that.
Mix the two in the tank and you will have excellent control (assuming you have no turf to worry about).