September Birth Flowers: Aster and Morning Glory (gouache style)

Aster comes from the Greek for star, a good description of the daisy-like flowers with their yellow centres. Many garden asters are North American plants now classed as Symphyotrichum, and they're often called Michaelmas daisies because they flower around Michaelmas, 29 September. Morning glory, Ipomoea, is a twining annual climber in the same family as bindweed. Its trumpet-shaped flowers open in the morning and fade by afternoon, and its seeds are poisonous.

Plant asters in spring or autumn in sun and soil that doesn't dry out. Some New York asters suffer from powdery mildew, so resistant kinds are worth choosing, and congested clumps can be divided in spring every few years. Their late flowers feed bees and butterflies well into autumn. Morning glory is tender, so sow it indoors in spring, nicking or soaking the hard seeds first. Plant it out once frosts have passed, in a warm, sunny spot with canes or trellis to climb.

Purple and mauve asters are set with blue morning glory trumpets on a soft blush ground. The colours run from violet into blue, the cool shades that take over borders in early autumn. Pairing the open, starry asters with the trumpet shapes of morning glory gives the picture two very different flower forms in one gentle palette.