Note on italicisation on plant labels:

For scientific purposes, the genus, species and infraspecies (below the rank of species) names (termed the generic, specific and infraspecific epithets) would be styled in italics and this may be requested by certain botanical institutions in their labelling. However, in general, for garden labelling it is usual practice for such italicisation not to be followed. Partly, this dates back to historical metal casting techniques of labels and also the introduction of the early engraving machines, for which the range of italic fonts was limited.