I'm not quite sure what the shaded ground technique is, but I would add mulch around the base of your vines anyways. It will allow for moisture retention, and as it begins to decompose, nutrients will be returned to the soil. I usually collect pine needles and put down a layer of them first. Pine needles are acidic, which also promites good hop growth. I then clean out the firewood shed and add the remnants of bark on top. It looks ugly, but effective. I have a picture posted on the "hop growing" child board. Most don't have access to these resources, so pick up a bag of mulch or two.