Salvia naming – good to understand for gardening, essential for science

To avoid confusion, it’s good to understand salvia naming conventions. There are a couple of ‘levels’ of naming, to do with whether a plant is a species as found in the wild, or a garden cultivar. I try to use standard naming as it minimises ambiguity.

Species

sage herb has the botanical name Salvia officinalis
Herb sage, Salvia officinalis

Botanists collect plants and name them in the binomial (two name) system of genus and species. Salvia is the sage genus, and for example ‘officinalis‘ is the herb sage species. The binomial is indicated by italics, i.e. Salvia officinalis. The genus gets a capital and the species is all lower case. Where it’s clear what the genus is (I’ve already established I’m writing about Salvias) this can be written S. officinalis. For every species there is a particular collected plant, dried and pressed in a herbarium somewhere, that has the defining characteristics.

Cultivars

Horticultural hybrids and crosses step out of this clear species system. New plants are named by their producers to distinguish them for gardening, which leads to a few issues. As the purpose of naming them is not to classify them but to identify or own them, the species is no longer relevant. In some cases the parents are known, and they can be described as crosses with an ‘x’, i.e. S. sagittata x macrophylla. A lot of the time though they are just given a totally new name i.e. Salvia ‘Amistad’ (showing the correct typography). Where the cultivar is not a inter-species cross it can be written in the form Salvia microphylla ‘Hotlips’.

Salvia subrotunda flowering
Salvia subrotunda, with species-type red flowers

As an example of naming for a cultivar, Salvia subrotunda is a red flowered species from South America. A white flowered form has been found, but flower colour is not a distinguishing attribute in the botanical sense, so it could be called Salvia subrotunda ‘white form’. However it has been named as a cultivar so its progeny should be called either Salvia ‘Caitymary’, or Salvia subrotunda ‘Caitymary’ (S. subrotunda is an annual, so the species is important information for cultivation).

The naming of cultivars is essentially uncontrolled, so there may be a large number of similar cultivars. S. microphylla is a particularly prolific species, with numerous and ever increasing cultivars which essentially differ only in flower colour. S. microphylla also crosses readily with S. greggii, and gardeners will say a cultivar is more one than the other, illustrating the danger of using species names in cultivars.

In my Salvia List page I have omitted the ‘ ‘ symbols for cultivar titles (and italics) just so all the species and cultivars list alphabetically.

Seeds vs cuttings.

It might be worth pointing out that variability is usually generated by sexual reproduction i.e. seeds, and salvias are particularly prone to interspecies crosses. It seems that many cultivars have been found as garden seedlings, and the parent plants inferred by the mix of characteristics. Guaranitica types seem to be particularly prone to this.

Propagation by cuttings or plant division stays true to type, and is thus invaluable for maintaining desirable characteristics. Cuttings are also necessary where a cultivar is sterile (won’t set seed).

Occasionally a new branch on an established plant will be a ‘sport’ i.e. spontaneously show different characteristics to the main plant, like variegated leaves. In this case cuttings will usually be true to the sport type, while seedlings from sport branches may revert to the normal type.