Half-hardy annuals are very sensitive to the cold, so need to be sown indoors in spring and planted outside in early summer when no more frosts are forecast. They'll keep going until the first autumn frosts.
Despite their exotic looks, half-hardy annuals are surprisingly easy to grow. Growing them from seed will give you a much wider choice of varieties than you’ll have if you buy ready-grown plants, and some species will flower in as little as 12 weeks.
Find out how to sow half-hardy annual seeds.
Prick out seedlings into pots or multi-cell trays and grow them on into sturdy plants, ready to drop into border gaps. Dot single plants as accents through your borders, or plant generous drifts between perennials, providing a contrast of foliage and colour.
Watch Monty Don's video guide to boosting borders with half-hardy annuals.
Here are 10 beautiful half-hardy annuals to grow.
Verbena x hybrida
Mildew-resistant Verbena x hybrida 'St George' has deep green foliage and a spreading habit. Stunning red and white flowers. Height: 15-25cm (6-10in). Flowers in 14 weeks.