My daughter has the invasive english ivy in a rock retaining wall between her property and her neighbors. They have pulled the ivy off the top and had it cut down as much as possible but it is still inside the rockery, and seems to grow again overnight. Is there anyway we can kill it off without poison, or covering the entire rock wall to prevent light getting in? The neighbors have put some flowers in some areas but, I know the ivy will just overtake everything again. Any info will be very helpful. Thank you so much.