Unknown spiny-leaved plant
Can anyone identify this plant. When the shoots appear, they're purple, but then it grows into this green plant with spiny leaves. I think they were planted in the spring, but can't remember what they were. There are no signs of flowers, but I wouldn't have bought something I didn't expect to flower, so will it flower eventually? The leaves are quite soft and limp, with many of the larger ones buckling under their own weight.