Yes, I call it a "flame thrower", but it's just a hose attachment to a propane tank. Turn it on high and blast those weeds - no chemicals and doesn't take long at all. Just used it today as a matter of fact!

Thanks for Weed Dragon advice ! It certainly is a lot of fun to burn the weeds up and it certainly works much faster than Roundup :) I will carefully consider if I want to go this route for 2 reasons: 1. Fire safety, it is very dry here in CO in summer so this might be dengerous to use. 2. Just like Roundup this method is post-emergent control and due to the size of the area to be controlled still going to present with same issue of being time consuming. I've been looking around some other pre-emergent control options and found a product called Preen (available from Amazon, Home Depot, Walmart, etc) -- this product is safe to use around trees and provides up to 3 months protection. So I think I will probably end-up with some combination of pre-emergent control (Preen, CGM) + Roundup/Weed Dragon for post emergent control -- even if I can get 50% weed reduction with Preen this will make post-emergent control so much easier. Thanks everybody for your help !! Please let me know if you have any other suggestion. Davie.

You need a weed torch. Good top kill, though perennial weeds will have to be burned off as they return. Heck of a lot faster and more convenient than boiling water. I don't know of any non chemical method of weed control that will translocate down through the roots. Here is a link that might be useful:

Do you know if they are annual or perennial weeds? If they are annual you could try throwing out some pre-emergent. Maybe its not the same weeds coming back but new seedlings. I like the blowtorch idea. Sounds like fun!