Open-Centred Dahlias Sue Drew Trriiallss Recorrderr,, RHS Garrden Wiisslley
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RHHSS PLAANNTT TRIALSS BULLLEETIN Numberr 24 Seepttemmbbeerr 22000099 Open-centred Dahlias Sue Drew Trriiallss Recorrderr,, RHS Garrden Wiisslley www.rhs.org.uk The RHS Trial of Dahlias Trial Objectives Trials are conducted as part of the RHS’s charitable mission to inform, educate, and inspire gardeners. The aim of the Dahlia Trial is to compare, demonstrate and evaluate a range of cultivars submitted by individuals and nurserymen. The Trial History of the Trial also allows for plants to be correctly named, described, Brent Elliott, Historian, RHS Lindley Library photographed, and mounted in the herbarium, providing an Dahlias were just being introduced into England at the time archive for the future. Cultivars are referred for further when the Horticultural Society (later to become the RHS) was assessment in the Trial. Following assessment in trial, those founded. John Wedgwood, one of the Society’s founders, was meeting the required standard receive the RHS Award of an enthusiastic grower of dahlias, and published an article on Garden Merit (AGM). them in the first volume of the Society’s Transactions . When the regular sequence of flower shows was begun at the Society’s garden at Chiswick in 1831, there were seven The Award of Garden Merit competitions set for their respective seasons, with the dahlia The Award of Garden Merit is only awarded to plants that are: competition taking place in September. ⅷ Excellent for ordinary garden use After the founding of the Floral Committee in 1859, a ⅷ Available programme of plant trials was begun, the trials taking ⅷ Of good constitution place at the Society’s garden at Chiswick. The first trial ⅷ Essentially stable in form and colour results to be published were for Pompon dahlias; the trials took place in 1862, and the report was published in 1863. ⅷ Reasonably resistant to pests and diseases Dahlias were included in a trial of bedding plants and ⅷ Reasonably easy to grow annuals in 1868. Trials specifically of dahlias did not recur until the 1890s. In 1895 a trial of Cactus dahlias was held at Chiswick. Another trial of Pompon dahlias took place in 1899, and further Cactus dahlia trials in 1900 and 1903. After the move to Wisley the trials resumed, with Cactus dahlias in 1905. y r All these trials had been for a r b i L dahlias in their decorative roles, y e l d as flowers for the greenhouse and n i L table decoration, not as flowers S H R for the garden. Reginald Cory, a Welsh coal millionaire and horticultural enthusiast (and future President of the National Dahlia Society), undertook to stage the first trials of dahlias as garden plants, and used his own garden at The Dyffryn, Reginald Cory Glamorgan, for the purpose. Virtually all the beds in his garden were turned over to dahlias for the 1913 trial, which was judged by a Joint Committee of the RHS and the National Dahlia Society. More than a thousand species and cultivars were submitted, and the RHS Journal published details of the uniform treatment each plant received to ensure that they were being judged to a common standard. The Gardeners’ Chronicle reported: ‘The Dyffryn gardens comprise upwards of 40 acres and the provision of flower beds and borders is so liberal that immense numbers of dahlias can be cultivated with ease, but this fact notwithstanding, the ground was planted up to the very last foot.’ Cory was given a Gold Medal for his work. Cory staged a further trial in 1914 but then came the First World War. As a precedent had been set for trialling dahlias as garden flowers, the process was resumed in the 1920s. Dahlias have been the subject of a standing trial ever since, with cultivars selected for trial by the Dahlia Sub- Committee, and reports published regularly. Front cover: Dahlia ‘Moonfire’ (Photo Sue Drew) 2 RHS Plant Trials Bulletin There are 13 different classification groups for dahlias. Only those with open centres (groups Dahlia Classifications 1, 3, 10, 12) are featured in this publication. Group 1: Group 6: Ball Group 11: Fimbriated Single-flowered Fully double blooms, Ray florets evenly split Single outer ring of ball shaped or slightly or notched into two or florets, which may flattened. The ray more divisions, overlap, the centre florets are blunt or uniformly throughout forming a disc. rounded at the tips, the bloom creating a spirally arranged, with fringed effect. Petals margins involute for at may be flat, involute, D. ‘Moonfire’ D. ‘Blyton Softer least 75% of the length D. ‘Anna Cozens’ revolute, straight, Gleam’ of the florets. incurving or twisted. Group 2: Group 7: Pompon Group 12: Single- Anemone-flowered Fully double, spherical Orchid One or more outer rings blooms of miniature Single outer ring of of generally flattened size, not exceeding florets surrounding ray florets surrounding 50mm in diameter, the disc. Ray florets a dense group of with florets involute for are uniformly either tubular florets, which the whole of their involute or revolute. are longer than the disc length. D. ‘Ryecroft Marge’ florets in Single dahlias, D. ‘Will’s Ringwood D. ‘Juul’s Allstar’ and showing no disc. Rosie’ Group 3: Collerette Group 8: Cactus Group 13: Double- A single outer ring of Fully double blooms, Orchid generally flat ray florets, the ray florets are Fully double blooms, which may overlap, usually pointed, the showing no disc. Ray with a ring of small majority narrow and florets are narrowly florets (the collar), the revolute for 50% or lanceolate and either centre forming a disc. more of their length involute or revolute. and either straight or D. ‘Don Hill’ D. ‘Lakeland Sunset’ incurving. D. ‘Mayan Pearl’ Group 4: Waterlily Group 9: Semi-Cactus Fully double blooms Fully double blooms, Lilliput dahlias characterised by broad, ray florets usually A low-growing type of dahlia usually generally sparse ray pointed, and revolute no more than 30cm in height having florets, either straight or for more than 25% of single, semi-double or double florets slightly involute along their length and less attaining 2.6cm or so in diameter. their length giving a than 50% of their Especially suitable for borders or shallow appearance. length (longitudinal display in containers on patios. D. ‘Charlie Dimmock’ Depth should be less D. ‘Julie’s Delight’ axis), broad at base and than half the diameter either straight or Dwarf bedding dahlias of the bloom. incurving. The use of ‘Dw.B’ after the classification of a cultivar indicates Group 5: Decorative Group 10: that these are dwarf bedding dahlias, Fully double blooms Miscellaneous not usually exceeding 60cm in height. showing no disc. The Any dahlias which do ray florets are generally not fall into one of the broad and flat, or listed groups e.g. Peony- slightly twisted and flowered dahlias. usually bluntly pointed, and may be involute for Source: Nineteenth Supplement to The Tentative Classified List and International D. ‘Dikara Midnight’ no more than 75% of D. ‘Bishop of Llandaff’ their length. Register of Dahlia Names 1969 (2007) Open-centred Dahlias 3 AGM = Award of Garden Merit This selection guide (H3) = hardy outside in some regions includes AGM dahlias or particular situations or which, while from a number of trials Selection guide usually grown outside in summer, and those of particular needs frost-free protection in winter. interest in the 2008 trial. ‘Ann Breckenfelder’ ‘Cascade Ken’ AGM (H3) 2004 Group 3 AGM (H3) 2006 Group 3 H: 140cm FD: 10cm H: 170cm FD: 12cm Flower vivid red, streaked yellow Velvety, dark red flower. Golden on reverse; collar green-yellow yellow disc. Raised by J Thompson. flushed vivid red at base. Yellow- orange disc. Raised by C Geerlings. 4 1 ‘Bishop of Llandaff’ ‘Chessy’ m u i r a b r AGM (H3) 1995 Group 10 AGM (H3) 2002 Group 1 e H S H: 100cm FD: 10cm H: 40cm FD: 5cm H R / l l Flower brilliant red, semi-double. Flower yellow. Disc lime-yellow. a d n Disc black and bright yellow. Raised by Topsvoort. e R a Deep blackish red foliage. Raised n i 12 r by Treseder. b e Z 1 C a m r ‘Brookfield Delight’ ‘Clair de Lune’ u o i r l i a n b e r e B AGM (H3) 1999 Group 1 AGM (H3) 1995 Group 3 e H c S k H: 70cm FD: 4.5cm H: 130cm FD: 12.5cm H R Flower orange-red. Disc red- Light to creamy yellow flower, brown with golden yellow. Dark collar paler. Deep yellow disc. foliage and stems. Raised by D G Raised by J Maarse. Rowlands. 1 12, 14 k CANDY EYES (‘Zone 10’) ‘Collerette Princess’ c e B e n i Group 1 AGM (H3) 2006 Group 3 l o r a H: 95cm FD: 8cm H: 154cm FD: 7.5cm C Flower deep purplish pink with Flower bright pink with a central white at margins and reddish band of dark red, white tips. orange at base. Disc orange- Collar white. Yellow disc. Raised yellow with dark orange. Raised by C Geerlings. by K Hammett. 5 1 ‘Carreg Cyril’s Girl’ ‘Don Hill’ Group 3 AGM (H3) 2005 Group 3 H: 123cm FD: 10.5cm H: 139cm FD: 10cm Flower apricot-orange, collar Burgundy flower, collar red with touched yellow with pale tips. white tips and flecks. Yellow disc. Disc orange-yellow. Raised by Raised by D A Reid. C Bright. 6, 11 11 4 RHS Plant Trials Bulletin Key Key to suppliers H: Plant height 1 Widely available, see 6 Halls of Heddon 12 The National Collection FD: Flower diameter RHS Plant Finder 7 JRG Dahlias of Dahlias 2 Aylett Nurseries Ltd 8 Rose Cottage Plants 13 Todd’s Botanics Measurements given Green Bronze Suitable 3 Binny Plants 9 Sampford Shrubs 14 Usual & Unusual Plants are taken from the foliage foliage for 4 Dan’s Dahlias (USA) 10 Southon Plants plants in trial.