One tuber. An entire summer of theatre. Hard to believe that the brown tuber in your hand can unleash such a thing. There are flowers you plant because they are useful, and flowers you plant because they behave beautifully. And then there are dahlias.
Dahlias flower from high summer until the first late-autumn frost. The grandest of them all is the dinner plate dahlia, and this story is about her — above all ‘Café au Lait’ and her pink cousin ‘Café au Lait Rosé’.
What a dinner plate dahlia is
The name caught on because it is true: the flowers are as big as a dinner plate. The official dahlia classifications do not use it at all; they call these varieties “giant” or class AA, blooms of about 25 cm across and more. In German they are Tellerdahlien or Riesendahlien, and the catalogues say both.
Dahlias come in very different heights, which matters when you choose for a bed, a pot or a border. Austrosaat lists tall and low dahlias in its spring range, as tubers, not seed. The decorative dahlia ‘Eveline’, for instance, white with a lilac heart, grows to 100 cm and flowers from July to October (item 110).
If you start with one variety, make it an extraordinary one: ‘Café au Lait’ in apricot and cream, or ‘Café au Lait Rosé’. For contrast, a second, smaller one — pompon dahlias in jewel colours that cut well. The mix is what makes the drama.
Where the name comes from
Anders Dahl (1751–1789) was a Swedish botanist and physician, a student of Carl Linnaeus at Uppsala. He never saw a dahlia; he died at 38. The plants themselves were grown by the Aztecs, recorded by Spanish explorers, and reached Madrid from Mexico in 1789.
In 1791 Antonio José Cavanilles, director of the Royal Botanic Garden in Madrid, described the plants grown from Mexican seed and named the genus after Dahl, honouring him and the Linnaean school. Dahlias reached Germany in 1805 and were renamed there after the naturalist Johann Gottlieb Georgi; in Austria you still hear “Georginen” today.
Botanically it is simple: genus Dahlia, daisy family (Asteraceae). The garden dahlias are hybrids, usually listed as Dahlia × hortensis, in older books also as Dahlia variabilis or Dahlia pinnata. A cultivar is written Dahlia ‘Café au Lait’.
Their variety is built into their genes. Dahlias carry eight sets of chromosomes where most plants have two; every seedling can look completely different in colour, size and shape. Breeders sow thousands of seeds, keep the rare exceptional ones and propagate them from tubers or cuttings so they stay identical. That is how a handful of wild Mexican species became tens of thousands of varieties.
From show flower to wedding flower
Giant dahlias are nothing new. In the 1830s and 1840s Britain went through a dahlia mania, with societies, shows and high prices for new varieties. Growers in Britain, the Netherlands and the US competed for ever-bigger blooms, and “giant” became a show class of its own. Classics like ‘Kelvin Floodlight’ (yellow) and ‘Thomas Edison’ (purple) were around long before weddings made dahlias fashionable.
‘Café au Lait’ came much later. It was bred by the Dutch nursery Bruidegom in Baarn and introduced in 1968, though some sources say 1966 or 1967: an informal decorative dahlia with blooms up to 25 cm. For decades it was a good garden dahlia but not a star; big decorative dahlias were seen as old-fashioned show flowers.
Fame came through Martha Stewart. After a feature in Martha Stewart Weddings the variety sold out; florists saw that its coffee-and-blush colouring suited the muted, romantic bouquet style that was coming in. In the 2010s small cut-flower farms and Instagram made it the wedding flower, some 40 years after its introduction. In 2021 Bloomberg reported that US supply had at times struggled to keep up.
‘Rosé’, ‘Royal’, ‘Supreme’ and ‘Twist’ were not crossed from other dahlias. They are sports: colour mutations that appeared on a few ‘Café au Lait’ tubers. Most growers throw such tubers away; Dutch growers kept and propagated them. Sources differ on who introduced which — Van Schie and J. van der Linden & Zonen are both named. They grow and flower just like the original; only the colour differs.
The boom did not create dinner plate dahlias. It revived interest in flowers breeders had been working on for over 150 years. Nurseries brought out the giants they already had — ‘Penhill Watermelon’, ‘Otto’s Thrill’, ‘Labyrinth’, ‘Emory Paul’ — and bred in the direction that sold: blush, peach, coffee and “antique” shades.
Where to grow them, and with what
With an endless palette of colour, shape and size, dahlias find a home anywhere, from pot to plot to long rows. It is wise, all the same, not to mix them too closely into a perennial border, because at the first frost they have to be singled out and dug up. Many gardeners, me included, give them a row of their own, mixed with other dahlia varieties. That makes the caring easier: the staking, the deadheading, the yearly planting and lifting.
Monet knew about their impact, too; dahlias still stand in the garden at Giverny. Here the rudbeckia stand behind the dahlia row, and ‘Café au Lait’ goes especially well with cosmos.
Smaller varieties make good supporting actors: ‘Moor Place’ (dark red pompon), ‘Franz Kafka’ (pink pompon) or a pompon mix. From Austria come Peter Haslhofer’s ‘Hapet’ varieties (Peters Dahlien). A warning: the popular varieties sell out quickly in the season, and nobody grows just one dahlia for very long.
Preparing the bed
Dahlias want rich soil and good drainage at the same time. Sarah Raven plants hers at Perch Hill about 50 cm apart, with plenty of grit and manure dug in. Loosen heavy clay with sand or perlite and add aged manure, but not too much. Clear weeds and grass first; compost helps sandy soil hold moisture and clay soil drain. And do not plant into cold, wet soil: the tuber stays dormant too long and rots easily.
Slugs
Slugs are the bane of every dahlia grower. They nip a display in the bud, quite literally, by feasting on the young shoots. Everyone has their own way, pellets or collars. In my location and climate, patience has worked best: I keep the dahlias in the glasshouse until they have built strong base leaves, and plant out only once the tender young growth that slugs love most has given way to tougher, more leathery leaves. By then the plants are established, and the slugs have to look elsewhere for their dinner.
Deadheading
Deadheading has to be done, and I have come to love it. Snipping off faded blooms lets the plant put its energy into new buds, so the flowers keep coming until the first frost. Old heads turn brown and soggy, and on dinner plate dahlias they are so large that they mar the fresh blooms beside them.
I do not throw them away. I drop them on the ground beneath the plants, where they break down as mulch and feed the soil. On a quiet evening, moving from plant to plant with my snips, it hardly feels like work at all.
Staking
Dinner plate dahlias in particular need support, and the stakes are best put in when the tubers are planted. I use painted stakes, an idea born of my re-creation of a Blue Stick Garden: Claude Cormier designed it in 2000 for the first International Garden Festival at the Reford Gardens in Québec, from wooden sticks with three blue sides and one orange, so the colour changes depending on where you look from (CCxA). The multicoloured stakes work really well, because stakes are the Achilles heel of dahlia presentation.
Overwintering
In cooler climates, dahlias have to come out of the ground at the end of the season. Most growers wait until the first frost has blackened the foliage; some lift a little earlier. Dahlias in pots need the same care: a pot offers no real protection, and frozen tubers do not survive. Nor do they like being waterlogged; in cold, wet soil the tubers rot.
It is hard work and perhaps the least glamorous part, but it has to be done. The tubers are dug up, left to dry and packed into a storage medium; I use sawdust, others use soil. Then they go somewhere cool, airy and frost-free until spring.
Dividing and labelling
Dahlias grow from tubers, the plant’s food store, and over the summer they make new ones, so the clump gets bigger every year. Dividing gives you more plants, though I admit I am not particularly gifted at it. Luckily plenty of capable gardeners show exactly how it is done in podcasts and clips.
The key is not to cut off the wrong part: each piece needs a bit of the old stem, where the new shoots form, or it will not grow. And label everything you divide, because sooner or later we all lose track. The labels also tell you which varieties are thriving and which are quietly disappearing. Without them you one day find yourself before a sea of white dahlias, wondering where that special one you bought has gone.
Further watching
- Sarah Raven, “Planting out dahlias” (video on sarahraven.com): the trial beds at Perch Hill, soil and spacing.
- Epic Gardening: Dahlias: every planting step on video.
- Longfield Gardens: “Planting out dahlias”, step by step.
- Austrosaat, spring-planted bulbs 2026, the dahlia pages.
- Gareth Rowlands, The Gardener’s Guide to Growing Dahlias.
