Abstract: One form of the invention employs two each of two different flexible parts to provide a soil retainer for plants on a hillside. Each part has one straight edge, an opposed slanted edge, a first side having a first pattern of hinge knuckles and a second side having a second pattern of hinge knuckles. The slanted edges are reversed in direction in the different flexible parts and their hinge knuckles are complementary. A first pair of two different parts is assembled by fitting their first hinge knuckles together and a second pair of parts is similarly assembled. The second pattern of hinge knuckles of the two pairs of parts are assembled. Long, staple-like pins fit through the holes of assembled knuckles and are driven into the soil. The retainer extends higher on the uphill side and lower on the downhill side. To increase the circumference of the retainer third parts may be inserted between the parts of one or both pairs.