Stewart Garden Cotswold Square Planter, £19.99

Despite thin and flexible side walls, the Cotswold range is made from premium-grade plastic and is frost-proof, shockproof and UV-resistant. It resembles, as its name suggests, natural Cotswold stone, with a textured, ‘hand-made’ look to the finish. Size 32x32x34cm (12½ x12½x13½in) high. Other sizes: 38cm (15in) square, £23.99