July Birth Flowers: Delphinium and Water Lily (gouache style)

Delphiniums belong to the buttercup family, and their name comes from the Greek for dolphin, after the shape of the flower buds. They're tall perennials with dense spires of spurred flowers in blue, purple, white and pink, and every part is poisonous. Water lilies, Nymphaea, root in the mud at the bottom of a pond and send up round floating leaves. Britain's native species, Nymphaea alba, is white, and the flowers open in sunshine and close at night.

Plant delphiniums in spring in a sunny, sheltered spot with rich soil, and stake them early, while the shoots are still short. Slugs love the young growth, so check plants often in spring. Once the first spires fade in July, cut them back and feed, and you'll often get a second flush. Water lilies go in from late spring to early summer, in aquatic baskets topped with gravel, set at the depth the variety needs. They flower best in full sun.

Tall blue delphiniums share a summer border with pink water lilies, poppies and roses. It's an imagined gathering, since water lilies belong on a pond, but it lets both of July's flowers appear side by side. The blue spires bring height and the pinks bring warmth, the way a border looks at its peak.