Knautia arvensis, field scabious, 1.8 litre pot
A fabulous wildflower relative of Scabiosa, producing masses of pale lilac pincushion flowers on wiry stems above low clumps of rough green leaves. Loved by all sorts of pollinators including bees and butterflies, and flowers from spring until winter for me. Handles most soils and garden conditions but flowers best in average-good garden soils in a sunny-ish spot. Will self-sow, so keep it deadheaded unless you want seedlings. Flowering height 70-90cm, spread 30-40cm. 1.8 litre pot.