Lythrum salicaria ‘Robert’
A tall, clump-forming, herbaceous perennial which has erect, branching stems bearing linear to lance-shaped, mid- to dark green leaves. From early summer to early autumn, slender, spike-like racemes of purple-pink flowers are borne.
Grow in any moist soil in full sun. It will reach a height of 1.5m and a spread of 50cm.