If you are a dedicated organic, then get some 20% vinegar
and put 2 oz of orange oil and one tablespoon of dishwashing liquid.
Use this concoction when it really gets hot and it will kill anything
it touches in 30 minutes. Doesn't kill the roots but really does a
job on anything on top.

Dishwashing soap is some pretty nasty stuff. Does it really count as
organic?

Cindy