There are three ways to grow dahlias: from rooted cuttings, tubers or seed.
Rooted cuttings are shoots taken last winter from the basal growth of the parent, rooted into compost and sent out bagged up in plastic, ready for potting up. They usually make smaller plants in their first year, but are big enough for pots, with plenty of flowers. Rooted cuttings are usually bought by mail order from specialist nurseries.
Here's how to grow dahlias from rooted cuttings.