Posted: 12/01/2015 at 18:29
Yes you could rotivate gravel/organic material in and then wait to see what annual weeds germinate which would be easy to hoe off but do check you haven't got perennial weed roots in there as that will be aright pain when they are all chopped up and will delay your plans as you wait around to glyphosate, possibly several times for perennial nasties. You will want to avoid the area round your tree as well as you will damage the roots or rotivator. I have actually read that using a rotivator does more damage to soil structure but I can't remember why. I am also on clay!