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I’ve Never Met a Hardy Geranium I Didn’t Like

October 21, 2009

Geranium x 'Brookside' (photo credit: Jean Potuchek) Say “geranium” and most Americans think of the annual geraniums that are ubiquitous around here in hanging planters for Mother’s Day and in pots for decorating graves on Memorial Day. These “geraniums” are actually flowers of the genus Pelargonium. Many Americans are completely unaware of the true geraniums, the hardy plants that are such marvelous garden perennials.

The hardy geraniums (also known by the common name “cranesbill”) are a wonderfully diverse genus.  In the 2nd edition of Herbaceous Perennial Plants, Allan Armitage puts the number of distinct species at “over 250.” In the second edition of his major reference work Hardy Geraniums (Timber Press, 2001), Peter Yeo puts the estimate somewhat higher, at 350 species. The number of geranium species seems to be difficult to count, in part, because of their tendency to form hybrids. Apparently, some geranium species are quite promiscuous, and if two species that are attracted to one another find themselves growing within spitting distance, they will happily interbreed and form hybrids. As a result, many of the geranium hybrids that are available to gardeners have not been intentionally bred by hybridizers but discovered by horticulturalists.

Silvery bloom of Geranium x oxonianum 'A.T. Johnson' (photo credit: Jean Potuchek)Hardy geraniums are primarily cool temperate plants, and those who garden in a cool temperate climate will have a dizzying array of geranium varieties to choose from. But there are many geraniums available even for those of us who live in less temperate climes;  there are geraniums that will grow as far north as USDA hardiness zone 3 and as far south as zone 8. Geraniums are not prone to disease, and they are adapted to a wide variety of garden conditions. Some, like G. cinereum, G. dalmaticum, and G. x cantabrigiense, are groundcovers that grow less than 12” tall. Others, like G. pratense, G. sylvaticum and G. psilostemon form clumps that can grow to 3 or 4 feet in height. Some geraniums will grow in full sun, while others prefer part shade. Some (e.g., G. himalayense, G. pratense) like moist locations; others prefer dry (e.g., G. macrorrhizum) or well-drained ( e.g., G. endressii) soil. Some (e.g., G. clarkei) bloom in spring; others (e.g., G. pratense) bloom in summer; and, if temperatures are cool enough, some (e.g., G. endressii) will bloom continuously through summer and into fall.

Geranium x cantabrigiense 'Biokovo' (photo credit: Jean Potuchek)

Colors on geranium blooms range from magenta through blue and violet, to pink and white. (I am unaware of any hardy geraniums with flowers in the yellow-orange range.) For the most part, the flowers are small and delicate rather than large and showy. But a stand of G. x magnificum with its blue flowers all in bloom can be breathtaking, and masses of G. x cantabrigiense ‘Biokovo’ flowers have a frothy appearance that always reminds me of whipped cream. Recently, Allen Becker’s blog featured a very showy G. psilostemon cultivar called ‘Patricia’ that I am eager to try out in my garden.

If you are not growing hardy geraniums yet, check them out; I’ve never met a hardy geranium that I didn’t like. In my next post, I will say more about the ways I am using hardy geraniums in my own garden.

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16 Comments leave one →
  1. October 21, 2009 9:12 am

    I need to research these more to see if I can use them in my hot garden. We don’t lose plants to cold here, as a rule, but the heat of summer has killed many plants that were not suited to it.

    Very nice post.

    • Jean Potuchek permalink*
      October 24, 2009 6:53 pm

      Janie, I think you’re right to be cautious about adding hardy geraniums to your Texas garden; it’s easier to find cold-tolerant plants (at least to zone 4) than heat-tolerant. If you decide to try them, a spot in the garden with shade during the hottest part of the day would probably work best. The most heat-tolerant varieties seem to be G. maccrorrhizum (a groundcover type and one of the parents of the Biokovo hybrid cultivar whose blooms remind me of whipped cream), G. sanguineum and G. sylvaticum (both taller, clump-forming types). All of these bloom in spring, presumably before weather gets really hot. G. x magnificum (with big blue flowers that really are magnificent!) is also rated as hardy to zone 8, but it blooms in summer so it would probably be a bigger risk. If you try any of them, let me know how they work out. -Jean

  2. October 21, 2009 10:25 am

    I am not so good with plant names, but I think these are native in my area. (rockymtns)
    I have been lucky to have them re-seed and add care-free beauty to my garden, plus the voles don’t eat them at all. YEAH!!!
    Rosey

  3. October 21, 2009 10:40 am

    I never saw a picture of a geranium that I didn’t like but they do not thrive here, except for the weedy Wild Geranium, which is a late winter annual here, dying off when the weather warms.

    I sometimes let Wild Geranium grow in a rich bed, where it makes a passable specimen and will crowd out less desirable weeds like Chickweed.

  4. October 21, 2009 11:34 am

    Hardy geraniums were the first plant I fell for in a big way over twenty years ago and the love affair continues 🙂 Look forward to your next post.

  5. October 21, 2009 4:53 pm

    Great post, Jean. More people need to know about these “geraniums.”

  6. elephant's eye permalink
    October 21, 2009 5:15 pm

    Wow! We only have Geranium incanum in South Africa. My summer snowflake.

  7. October 21, 2009 6:45 pm

    Hello Jean,

    What an informative post. As a Horticulturist myself, I love that people in my profession are those that have discovered the new hybrids!

  8. October 21, 2009 10:19 pm

    Jean, I think that perennial geraniums were one of the first plant families that I grew to love. I started with Johnsons Blue, that beautiful plant that was so common a few years ago. I have grown Patricia in the past, she is beautiful, a really intense colour. Ballerina, a cinereum is another fav, lovely pink flowers with a purple eye and veins. I also have a lot of macrorrhizum, great as a ground cover/weed supressor for me, a weekend gardener. I just bought the variegated version as well!
    Deborah

  9. October 21, 2009 11:59 pm

    I love these plants and have 3 or 4 varieties. Would love to have 250! Thanks for this post!

  10. October 22, 2009 3:11 pm

    Unfortunatly the only “Geraniums” I’m familiar with are the ubiquitous Pelargonium that you speak of . Thanks fro a well written and informative post regarding a genus I’m unfamiliar with.
    Scott

  11. October 24, 2009 10:39 am

    I’m glad I visited your blog and your photos are so pretty and sharp. I love geraniums, as well!

  12. October 24, 2009 12:07 pm

    I grow Johnson’s Blue and Rozanne in a patch under my lilac tree and love the way a group of these looks. I also have what I think is a G. pratense, but it’s a little floppier. The geraniums don’t need a lot of fussing, which is always a bonus.

  13. October 24, 2009 11:37 pm

    I have enjoyed growing several kinds in my curb beds. I moved some to my garden across the street last spring because I had to take things out 18 inches from the street when they put in new curbs this summer. As it turns out, I moved more of them than I needed to, because they didn’t have to replace the curved part. As it turns out, they seem to like the moister more shaded area than where they came from, so I didn’t have the heart to move them back, but think I’ll divide them in the spring and have some in both areas. Maybe I’ll get some new ones, too.

  14. October 25, 2009 10:46 am

    I really like this post! I just learned this year, through blogging, about the ‘perennial’ geranium types. That was an eye-opener. I then purchased several including Johnson Blue and Rozanne. They do fine in my zone 7 garden. I think I’ll add a few more varieties next yr.

  15. Colette Dunkley permalink
    March 22, 2011 8:19 am

    A couple of the most troublesome and persistent weeds in my garden are perennial geraniums Geranium “Celtic White” and that lilac one with shiny green leaves and a penetrating rootstocks with red growing points . ( The name eludes me just now but Corol Klein who I love recommends it but I loathe it with a vengeance) I would only ever have the well behaves G ” Himalayan White / Purple & mrs Kendal Clark in future

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