Geranium or Pelargonium? Let’s Stop the Confusion

Your 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, 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.

This is Geranium sanguineum, a true 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”.

To Beak or Not to Beak?

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 say “scented pelargonium” in a lecture, there are very few confused faces: almost everyone gets it right away. And this had 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, but that trait has been bred out of many of them.

    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.):

    Geraniums always have symmetrical flowers.

    Cold-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.

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

  1. Georgina Paterson

    Great to get this clarification and I can clearly see the difference with the 2 examples you have used. As someone else said – pelargoniums are very popular in Australia. A bit of an old-fashioned favourite. One more question I have – is regarding the hanging variety. The kind you see in Italian window boxes. These have a shinier, less furry leaf and often called “ivy geranium”. Are they in fact a pelargonium rather than a geranium?

  2. Pingback: Historic Company’s Garden in Cape Town - Travel to Eat

  3. Donley Wilson

    Thank you for the clarification. Been gardening for 50 years in San Diego. Always new of both and always ment to find the difference..
    Mother has a fine begonia at her front door. Must be at Ieast 50 yrs old. And may have restarted itself as well.

    Thank you Miss Rose for the toxicity question. Need to find out now just why the pelargoniums are poisonous.
    That alone should signal a species break.

  4. Robin Cardier

    I don’t think I’ve ever seen a true geranium. I live in Queensland, Australia, and our ‘geraniums’ are all pelargoniums, tough as bags in our climate! They live for years out in the garden, the only thing that kills them is overwatering, which makes the stems go soggy.

    • Quite a difference in Canada. Where I live (a bit cold even by Canadian standards), we literally have 6 to 7 months where temperatures are below freezing most of the time! We have all sorts of true geraniums in our gardens, but nary a pelargonium survives the winter!

  5. Pingback: BLOOM THYME FRIDAY: LET THE SUNSHINE in – The Garden Diary

  6. Esmond Wayne Dowdy

    I get the point about symmetric and asymmetric flowers – but lots of plants have very complex flowers. muiltipetalled and often very frilly. It’s hard to determine symmetry with these flowers.

  7. LaVerne Rose Moore

    Which one, may I ask, is toxic to dogs ?

  8. Elisabeth Bollman

    Hi, I love pelargoniums because they remind me of my grandmother’s garden, but they are very hard to find in No. California nurseries. I guess because they are less hardy. Why have the asymmetrical flowers been bred out of them? That’s part of their charm.
    Wish they could be bred to be hardier.

  9. Hi hope you can help me. Generally I am very successful with geraniums but I have a love bushy pelargonium but not flowering. Any hints?

    • There are many, many species of pelargonium, not all of which are heavy bloomers. Try increasing the amount of sun and cutting back on fertilizer.

  10. Pingback: Are We Participating In The Spekboom Challenge? - Small Scale Engineering

  11. Thank you. I learnt something new today – I had them completely around the other way, or just thought they were all geraniums. I have several of the “true” geraniums doing very well (aka taking over some areas) in my temperate/sub-alpine shady garden (Victoria, Australia). I also have a number of what I thought were geraniums, but now know are pelargoniums doing ok (tend to get very leggy), and they survive winter outside no worries – however, we rarely get snow and do not get frosts, so maybe that is why?

  12. John-Paul Leonard

    I’m looking for a quick guide to tell true geraniums apart from pelargoniums. It seems we have both kinds and one of my big climbing geranium plant is not doing well.
    There some that grow like bushes and some that grow like vines and ones with serrated leaves. Which is which

    • Pelargonium flowers have 2 upper petals and 3 lower ones: the lower ones are usually smaller. Geranium flowers have 5 petals too, but naturally symmetrical and of equal size. That’s the basic rule. However, some hybrid pelargoniums have been bred with equal-sized petals, so they are exceptions.

      Other than that, there are no shrubby or climbing geraniums, so those must be pelargoniums. Also serrated leaves are likely linked to pelargoniums.

      My guess is that all your plants are pelargoniums.

  13. Pingback: Geraniums or Pelargoniums? | Kiyanti2008's Weblog

  14. Thank you. It’s better for me not to beak ….. now I know for sure that all my geraniums are actually pelargoniums. I hope you don’t mind if I link this blog to mine.

Leave a Reply