Perennials and biennials that earn their space

Perennials are slower but give you structure. In a tiny space, every plant must justify itself — no passengers. Asters, heleniums, and daylilies look fine in a border but offer only short vase life and take up too much room. Instead, choose plants that produce multiple flushes or long-lasting stems. Achillea 'Terracotta' and 'Cloth of Gold' flower from June to September if deadheaded; the flat heads dry beautifully. Astrantias like 'Roma' and 'Claret' thrive in part shade, tolerate containers, and produce wiry 60cm stems all summer. Each clump yields twenty to thirty pickable stems.

Perennial sweet peas (Lathyrus latifolius) are the lazy gardener's triumph. Plant one 'White Pearl' or 'Rosa Perle' in a 30cm pot, give it a support, and it will climb to 2m and flower from June to October with zero maintenance. The flowers lack scent but last five days in water and the plant is bone-hardy. Similarly, Japanese anemones like 'Honorine Jobert' (white) and 'Pamina' (deep pink) deliver elegant stems from August onwards when most annuals are flagging. One plant in a large container gives you eight to twelve stems a week for six weeks.

Biennials are the overlooked middle ground. Foxgloves, honesty, sweet rocket, and forget-me-nots all self-sow once established, giving you a renewable crop. Foxgloves like 'Sutton's Apricot' and the white Digitalis purpurea f. albiflora reach 150cm and produce side spikes after the main stem is cut. Lunaria annua (honesty) gives you purple spring flowers followed by translucent silver seedpods that last months in a dry arrangement. Hesperis matronalis (sweet rocket) is the scented, pastel-toned cottage classic that flowers in May and tolerates shade.