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Dahlias are invaluable for the summer border, in patio containers or as cut flowers, often flowering until the first frosts. With many excellent recent introductions, they offer a wide range of flower types, often with very showy, double forms in warm vibrant colours. Dahlias are enjoying a much deserved return to popularity.
Dahlia ' Freya's Paso Doble' (Anemone-flowered)
Dahlias are easy to grow but do need winter protection in most parts of the UK. They are tolerant of a wide range of soil types and situations but best planted in fertile, well-drained soil in full sun when danger of frost is over, usually May to early June. Planting could be carried out slightly earlier in southern counties or later in the north of England and Scotland.
Cut plants to the ground after the first frosts have blackened the foliage. In mild regions and on well-drained soils, leave the tubers in the ground and cover with a 7.5-15cm (3-6in) deep layer of bark chips or garden compost to protect them from frost. In colder areas or on heavy soils, lift and store the tubers (see below) and replant the following spring.
There are many great dahlias to choose from for the garden. Pick from the handful below or see a fuller list in our Find a Plant here.
Dahlia ‘Bednall Beauty' AGM: (Misc/dwb) (Miscellaneous Group) dwarf bedding dahlia. With deep bronze-purple foliage and dark red double flowers. Height 50-60cm (20in-2ft)D. ‘Bishop of Llandaff' AGM: (P) Peony-flowered (Miscellaneous Group) dahlia with almost black foliage and semi-double deep-red blooms. Height 1m (3¼ft) D. 'Hadrian's Sunlight' AGM: (Sin) A single flowered dahlia with yellow flowers and a central darker yellow-orange ring, faint orange and purple veining on reverse. Glossy dark purple foliage. Height 1.2m (4ft)D. 'Kenora Sunset' AGM: (S-c) Bicoloured medium semi-cactus flowers, bright lemon-yellow at the base with bright red tips. Dark green foliage. Height 1.2m (4ft)D. merckii: A tough species (Botanical Group) dahlia, multi-branched, with mid-green leaves composed of toothed leaflets and profuse broad-rayed lilac-pink flowers with yellow disc florets that open in loose clusters above the foliage. Height up to 1.5m (5ft)D. 'Pearl of Heemstede' AGM: (D) Decorative; dark green foliage, flowers are long stemmned silver pink with darker stripes. Height 1.2m (4ft)D. 'Small World' AGM: (Pom) White pompom like flowers with incurved petals, green leave. Height 1m (3ft) D. ‘Twyning’s After Eight' AGM: (Sin) A long-flowering stylish (Single-flowered Group) introduction with profuse ivory-white single flowers held on strong stems above almost black foliage. Height 90cm-1.2m (3-4ft)
Dahlia cultivar registration (held by the RHS)National Dahlia Society: for information on UK dahlia classification 2009, show schedules, history of the dahlia, species dahliasRHS dahlia trialsRHS AGMRHS Find a Plant
Dahlias can be prone to a number of pests, diseases and disorders;
Begonias: outdoorsCannaChrysanthemumsDahlia cultivar registration (held by the RHS)Exotic and subtropical plantsNational Plant Collection of DahliaNational Dahlia SocietyOverwintering tender plants: lifting or mulchingRHS open-centred Dahlias trials bulletinRHS video: Expert tips on National Dahlia Collection
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