Tradescantia (Andersoniana Group) ‘Carmine Glow’ or ‘Karminglut’?

Synonyms are a really BIG problem for gardeners in general and National Collection Holders in particular. When a plant becomes popular and sales increase, it usually isn’t long before a commercial plant nursery offers an extremely similar plant for sale under a different name. There might be a tiny difference in flower or leaf colour or no difference at all! They want more sales and if people are buying a particular plant they will also buy ones which are very similar, thinking they are getting something new and different. Collection Holders like myself might hunt down a plant with a name they don’t recognise only to find it is something else they already have but under a different name. This is very frustrating and can be time consuming and sometimes expensive. I would normally advise people only to buy from reputable sources but they are often the biggest culprits!

It seems to me that because Tradescantias are so promiscuous, and produce cross pollinated seedlings at the drop of a hat, this is why there are so many different hybrids, many of which are only subtly different to each other. On any given plant, not all the flowers will be identical, so are the two flowers featured above from the same plant or differently named plants? They are accepted by the RHS as different plants, ‘Pauline’ and ‘Pink Chablis’, but at several points last year both plants looked identical. The flowers seem to have stronger or weaker flower colours depending if they are grown in sunny or partly shaded positions, and colours seem to weaken as the flowering period comes to an end. Of course, there are many other differences and variations which characterise specific plants, not just flower colour, but these are often very subtle indeed!

A former Tradescantia National Collection Holder, Hazel Kaye, recently told me that she purchased a Tradescantia Andersoniana Group plant named ‘Bridesmaid’ at a plant sale in Leicester and believed she may have found something new. It turned out to be a self sown seedling from a local garden which the owner had named herself and which had not been trialled or tested before offering it for sale. It was a poor selection and not worth pursuing.

Tradescantia ozarkana – a species widely distributed in Missouri, Arkansas, and Oklahoma, USA

I am indebted to the Botany Advisory Services of the RHS who kindly allowed me to quote from their leaflet ‘Guide to Plant Names‘.

“Although the ideal is for each species or cultivar to have only one name, anyone dealing with plants soon comes across a situation where one plant has received two or more names, or two plants have received the same name. In each case, only one name and application, for reasons of precision and stability, can be regarded as correct. Additional names are known as synonyms.

In the past, and in the nineteenth century in particular, when a huge amount of botanical exploration was taking place, it was possible for botanists to be beavering away describing and naming plants in different parts of the world, blissfully unaware that they were duplicating someone else’s work. This is perhaps difficult to understand in these days of instant global communication, but it led to many cases of a single species with two or more names, or two or more species with the same name. The simplest way to resolve the problem of duplicated and superfluous names is to invoke a rule of priority – the earliest name correctly published wins and new names are therefore needed for some plants with later, incorrect names.

This is a basically sound idea but has led to changes of some very familiar, yet incorrect names due to the discovery of earlier, correct ones in very obscure texts. This can have a destabilising effect, contrary to the intention of the rule of priority, so there is now a much more pragmatic view being taken, with some of the more destabilising proposed name changes vetted by an international panel and often rejected if the technically wrong name is widely known. For example, the popular heather, Erica carnea, was saved in this way from being changed to Erica herbacea.

Cultivars acquire extra names in similar ways to wild plants and also through the deliberate re-naming when the original name is felt not to promote good sales! The same principle of priority applies for cultivars as for wild plants so there are always cases where correction is needed. However, it is not always appropriate to provide a new, unique name for a cultivar which has been given the same name as an existing plant. Where there are large groups of cultivars, such as in the genera Fuchsia and Pelargonium, repetition of cultivar names has proved difficult to avoid. In these cases, names can be qualified with the name of the breeder, the date of introduction or the plant type to help pinpoint their identity.

In the case of wild plants, correct identification and naming relies on knowing what species exist and how they are related. Add to this the increasingly reliable evidence of evolutionary trends provided by DNA and molecular studies and the fact that, for better or worse, the naming system aims to reflect the classification and therefore relationships, and it can be seen that some changes are inevitable….genera being split, new ones created, others amalgamated.”

This is a major source of irritation for National Plant Collection Holders as I have already said. In the main picture above, Tradescantia (Andersoniana Group) ‘Carmine Glow’ is the same plant as ‘Karminglut’ (which means Carmine Glow in German) and is recorded as such on the RHS database. However, I have discovered sellers who offer both as distinctive plants.

Likewise, Tradescantia (Andersoniana Group) ‘Sweet Kate’ (above) is a popular variety for sale in the UK due to it’s distinctive yellow foliage and mauve flowers. However, in the United States, I have discovered a virtually identical variety for sale on the internet called ‘Charlotte’s Web’. It remains to be seen if this is indeed the same plant but the images I have observed would suggest so.

As my Tradescantia journey progresses, I will no doubt be discovering many more instances of the same cultivar with different names and my collection will require constant scrutiny to weed out the synonyms.