Laidback Gardener Tip of the Day

Geranium or Pelargonium? Let’s Stop the Confusion!

This “zonal geranium” is really a zonal pelargonium (Pelargonium x hortorum).

For over 200 years now, gardeners have known that their garden geraniums (zonal geraniums, scented geraniums, ivy geraniums, etc.) were actually pelargoniums, that is, that they don’t belong to the genus Geranium, but instead to the genus Pelargonium. It was a simple mistake. Linnaeus thought the plants were close enough relatives to put both types in the genus Geranium. But Charles L’Héritier saw things differently and separated them into two genera in 1789. The change was widely accepted even back then and still holds today.

Le géranium vivace (ici Geranium sanguineum) est un véritable géranium (Geranium).

That wasn’t so much of an issue back when gardeners grew mostly pelargoniums (the annual types). If you used the word “geranium”, everyone understood you. But for the last 40 years or so, true geraniums (Geranium spp.) have become widely popular in temperate climate gardens. I mean, who doesn’t grow either G. ‘Rozanne’ or G.‘Johnson’s Blue’? To distinguish them from the tender (half-hardy) pelargoniums, few of which can survive the winter in temperate climates, we took to calling the latter “hardy geraniums”.

A Beak in Common

Both geraniums and pelargoniums have a similar long, narrow, beaklike seed capsule.

Of course, the two plant genera, Pelargonium and Geranium, are closely related. Both belong to the same plant family, the Geraniaceae, and both have the same long, narrow, beak-shaped seed capsule that springs open when ripe and casts the seeds far and wide. In fact, the botanical names both refer to this phenomenon.

Pelaragonium is derived from the Greek for stork, because the seed capsule is said to resemble a stork’s bill, while Geranium means crane, because it’s supposed to look like a crane’s bill. Honestly, you’d have to be a fairly serious birder to be able to tell a stork’s beak from a crane’s beak… especially if you removed the rest of the bird! The seed capsules, therefore, are essentially identical.

Time to Change

I think it’s time to stop pussyfooting around. Why not call a Geranium a geranium and a Pelargonium a pelargonium?

Again, most gardeners already know the difference and are familiar with the term “pelargonium” even if they don’t yet use it. For example, if I use the term “scented pelargonium” in a lecture, there are very few confused faces: almost everyone gets it right away. And this has become all the more necessary in that an increasing number of varieties in both genera are now being grown. When someone tells me about a new geranium they are growing, I like to know right away whether they referring to a geranium (hardy) or a pelargonium (tender).

For those who don’t quite get the difference, here’s a quick summary:

Pelargoniums (Pelargonium spp.)

  • Tender plants (not cold resistant);
  • Grown as annuals or brought indoors for the winter;
  • Most have sturdy stems, often upright, that survive from one year to the next;
  • 20150823D
    Originally, pelargoniums had asymmetrical flowers like the ones seen here, but that trait has been bred out of many hybrid varieties.

    Originally, all pelargoniums had asymmetric flowers, with two upper petals and three lower petals that are quite distinct, but that characteristic has been bred out of many modern pelargoniums. The average zonal pelargonium (Pelargonium x hortorum), for example, now has symmetrical flowers, with all five petals being identical.

Geraniums (Geranium spp.):

  • OLYMPUS DIGITAL CAMERACold-hardy (there are a very few exceptions);
  • Grown outdoors year round, almost never indoors;
  • Herbaceous perennials (they usually die to the ground or to creeping rhizomes in the winter, then sprout again in the spring);
  • Always have symmetric flowers: 5 petals of approximately equal size and shape.

So there you go. You may say po-TAE-to and I may say po-TAH-to, but let’s all say geranium when we mean Geranium and pelargonium when we mean Pelargonium.

Larry Hodgson is one of Canada’s best-known garden communicators. He has notably been editor-in-chief of HousePlant Magazine, Fleurs, Plantes et Jardins, À Fleur de Pot and Houseplant Forum magazines and is currently the garden correspondent for Le Soleil and radio garden commentator for CKIA-FM Radio. He has written for many garden publications in both the United States and Canada, including Canadian Gardening, Harrowsmith, Horticulture, Fine Gardening and Organic Gardening. He also speaks frequently to horticultural groups throughout Canada and the U.S. His book credits include The Garden Lover’s Guide to Canada, Complete Guide to Houseplants, Making the Most of Shade, Perennials for Every Purpose, Annuals for Every Purpose, and Houseplants for Dummies, as well as nearly 60 other titles in English and French. He is a past president of the Garden Writers Association (now Garden Communicators International) and the winner of the prestigious 2006 Garden Media Promoter Award offered by the Perennial Plant Association. He resides in Quebec City, Quebec, Canada.

0 comments on “Geranium or Pelargonium? Let’s Stop the Confusion!

Leave a Reply

Sign up for the Laidback Gardener blog and receive articles in your inbox every morning!

%d bloggers like this: