This perennial dies back to below ground level each year in autumn, then fresh new growth appears again in spring. Position: full sun; Soil: moderately fertile, moist soil; Rate of growth: average; Flowering period: July to September; Hardiness: frost hardy (needs winter protection) A tall, sun and moisture-loving perennial with slender branching stems that are clothed in aromatic green leaves, and from midsummer, topped with short spikes of sky blue flowers. A fairly fast grower, the flowers attract bees, butterflies and other beneficial insects, so it’s ideal for a wildlife-friendly garden, as well as adding drama and height to the back of a border; Garden care: To prolong flowering remove the flower spikes as soon as they start to fade. Apply a generous 5-7cm (2-3in) mulch of well-rotted garden compost or manure around the base of the plant in autumn. Protect from excessive cold.