In our fruit cage we have four beds of raspberries, one each of early, mid, and late season summer fruiting sorts, and one for autumn fruiting varieties. Each is around 9 by 5 feet, with a double row planted down the centre, around 2 feet apart. Some already have strawberries along the outside edge and all of them are intended to have them in due course. The raspberries vary in vigour but some of them are quite rampant, spreading out to take over the area reserved for the strawberries. Something needed to be done to keep them under control.
Whilst some raspberries are content to develop a stool of canes and are quite limited in their spread, others appear to put out lengthy runners and spread out of control. We were somewhat surprised by how rampant they had become, having not seen them behave this way before. To deal with it, we used a spade to create a V shaped trench along the length of the beds, on both sides, to separate the raspberry and strawberry areas, cutting through any runners at the same time. We removed those canes growing in the strawberry area, then inserted some of the plastic wavy edging used for lawns and such to prevent the runners coming through again and filled back. At 8” in depth, this should be sufficient to prevent the runners, most of which are scurrying around a couple of inches below the surface, from returning. How effective the plastic may be and how long it will last remains to be seen.