Dahlias are firmly back in fashion, and an essential element of the garden – they flower prolifically in a wide range of vibrant colours from summer well into autumn, and make excellent cut flowers.
Watch our video that reveals three golden rules for growing dahlias.
All dahlias are grown in the same way, but there are various groups of dahlia, with distinctive flower characteristics. Their classification is slightly complex, as there are thousands of varieties, bred all over the world, and suppliers may list them differently.
Here are some of the main types of dahlia that you’ll come across.
Single dahlias such as ‘Joe Swift’, pictured, and ‘Bishop of York’ have a single ring of petals that circle around a central disc. The petals may be rounded or pointed and may overlap. This type of dahlia is attractive to pollinators. Discover more single dahlias to grow.
Cactus dahlias such as ‘Doris Day’ and ‘Ryecroft Pixie’ have fully double blooms, with very narrow petals from the tip to the base, that often curve inwards. They range in size from miniature to giant. Discover cactus dahlias to grow.
Semi-cactus dahlias such as ‘Dame Deirdre’ (pictured), ‘Pink Preference’ and ‘Vulcan’ have fully double, fluffy-looking flowers. The petals have a broader base at the bottom than cactus dahlias and are rolled in for about half of their length. Discover more semi-cactus dahlias to grow.
The flowers of pompon dahlias such as ‘Moor Place’ (pictured) and ‘Franz Kafka’ are perfect spheres, formed of petals that are curved inwards. Their flowers are smaller than those of ball dahlias, below. Discover pompon dahlias to grow.
Ball dahlias including ‘Jomanda’ (pictured) and ‘Aurora’s Kiss’ are larger than pompon dahlias and have a spiral arrangement of curved petals that form a ball or a slightly flattened sphere. Discover ball dahlias to grow.
As their name suggests, waterlily dahlias including ‘Kilburn Rose’ (pictured) and ‘Taratahi Ruby’ resemble waterlily flowers – they have broad, shallow double flowers that are shaped like a saucer, with curved or flat petals.
Anemone dahlias such as ‘Lambada’, shown here, have an unusual look – they have tubular florets in their centre, surrounded by at least one ring of flatter petals on the outside.
Decorative dahlias such as ‘Checkers’ (pictured) and ‘David Howard’, have fully double, slightly flat and broad petals, often with a blunt end, and no central disc. They’re the largest of all the dahlias – flowers can be up to 25cm in diameter.
Collarette dahlias have overlapping, large petals that surround a ‘collar’ of smaller petals around a disc in the centre. They include ‘Chimborazo’ and ‘Yankee Doodle Dandy’ (pictured).