THE DIFFERENCE BETWEEN PELARGONIUMS & GERANIUMS
For those of you who have difficulty grasping the Pelargonium/Geranium naming issue I will try and keep it simple to explain how this confusion came about. The Pelargonium belongs to a family that was originally called Geranion which seems to have been changed along the way to Geranium. This family is divided into five and to make it easier to understand, I will call each of them a tribe. The five tribes are Pelargonium (storksbill), Geranium (cranesbill), Erodium (heronsbill), Sarcocaulon and Monsonia, as you can see from this one of the tribe, namely Geranium became the name for the whole family. The word Geranion was derived from geranos which in Greek means crane. This was adopted because the main distinguishing feature of the whole family is the extended beak-like seed produced by all its members. At a later date this was deemed wrong and the whole family was duly renamed Geraniaceae.
What you should be able to gather from this is that the Pelargonium is a tribe in its own right and apart from the beak-like appearance of its seed, bears no resemblance to the tribe Geranium. Where they also differ is that the Pelargonium has a nectar tube, this is joined to and forms part of the pedicel, which in layman's terms means individual floret stem. The Geranium does not have this luxury and also differs from the way it disperses its seed. The Pelargonium has a white feather-like end to its seed which allows it to drift away on the wind. The Geranium seeds once ripe are flung quite a distance from the parent plant as I have often noted in my Geranium bed. Another way they differ is that the Geraniums, apart from a few, are regarded as totally hardy, whereas the Pelargonium is more tender and needs to be given some protection during the winter months.
An obvious way to tell the two apart is to look at the flowers, on the Geranium the petals give the appearance of a regular formation whereas on the Pelargonium they appear more irregular being of different shapes, especially on some of the species.
When you go into your garden centres and nurseries to buy bedding geraniums you are really buying bedding Pelargoniums which have been raised for that purpose. The same goes for scented leaf Pelargoniums, these are sold as scented Geraniums, this is so wrong, ok some of the leaves on the Geraniums are pungent such as the Macrorrhizum group which are regarded more as aromatic rather than have a definite smell like the Pelargoniums which can be more pleasant with scents like Lemon, Orange, Peppermint, Pineapple and Ginger to name but a few. It is a shame that the powers to be do not put this right to stop all this confusion. The excuse that the public will not know what they are buying if the plants that are indeed Pelargoniums presently being sold as Geraniums are actually called by their proper name is wearing a bit thin in my opinion. I have been going around the country giving talks to specialist societies, garden clubs and horticultural societies for many years. In the beginning when I asked how many did not know the dfference between Pelargoniums and Geraniums, virtually everybody's hands used to go up - NOW THEY TELL ME!