The naming of plants is frequently a source of confusion and disagreement amongst horticulturalists and the following notes have been prepared to offer dahlia enthusiasts a clear guide to the framing, styling and registering of cultivar names.

The function of a cultivar name is to recognise and distinguish plants exhibiting desirable characteristics so that easy reference can be made to them. They appear at the end of the italicised latin name and are made to stand out from the botanical element by being enclosed in single quotation marks and not written in italics e.g. Dahlia ‘Glorie van Heemstede’.

Naming Cultivars

Cultivar names are usually bestowed by the raiser of a plant but the names that can be given to new plants are governed by the International Code of Nomenclature for Cultivated Plants (ICNCP). The seventh edition of this work was published in 2004 and outlines rules concerning the naming of horticultural and agricultural plants. A summary is provided below of those articles affecting people wishing to name new dahlias.

Art. 19.13 New names must comprise words in a language other than Latin unless they are common phrases or the names of people or places e.g. Dahlia ‘Variegata’ would not be allowed but Dahlia ‘Julius Caesar’ would.

Art. 19.19 & Art. 19.20 New names should not include the words form, variety, cultivar, grex, group, hybrid, maintenance, mixture, selection, sport, series, strain, improved or transformed.

Art.19.21 Punctuation marks should not be used with the exception of the apostrophe, full stop, comma, exclamation mark, hyphen, forward slash and back slash.

Art 19.23 A cultivar name should not contain the name of the genus to which it belongs e.g. Dahlia ‘Magnificent Dahlia’ would not be allowed.

Art 19.25 A cultivar name cannot be established if it is so similar to an existing name that there may be confusion. – Raisers should check with the RHS Dahlia Register.

Art. 19.26 New names cannot exaggerate the merits of a plant so Dahlia ‘Unsurpassably Blue’ would not be permitted.

Trade Designations

The expanding use of Plant Breeders’ Rights (PBR) has added confusion to the naming of plants. Although plants can be registered for PBR under conventional cultivar names it has become customary to register them under code or nonsense names. Such names, though unwieldy, are the correct cultivar names and must, by law, be used on labels at the point-of-sale. However, for marketing purposes it is sometimes necessary to provide a selling name or trade designation. Examples of this kind of name include Dahlia Royal Dahlietta Caroline (‘Dapavio’) and Dahlia Royal Dahlietta Emily (‘Daparos’). Note that the trade designation is distinguished by being printed in a different typeface while the cultivar name is enclosed in single quotation marks.

Series Names

Series names are marketing devices and should not be confused with classifications such as lilliput, ball or decorative. Plants included in a series usually have a common growth habit and flowers in a range of colours, each colour with a different cultivar name. Dahlia ‘Gallery Monet’ and Dahlia ‘Gallery Leonardo’ are included in the Gallery Series for commercial purposes but they remain classified as miniature decoratives.

Registration of Names

The RHS Dahlia Register currently contains around 17,500 names and is an invaluable resource in ensuring the same name is not repeated, that very similar names are not used and that new names conform to the ICNCP. In addition, it provides information concerning the classification, colour and raisers of registered dahlias. It is beneficial to breeders and gardeners alike if new cultivars are registered before a new plant is released. Registration forms are available from the Dahlia Registrar, RHS Garden, Wisley, Woking, Surrey GU23 6QB.