Everybody knows geraniums--or at least think that they do! After all, those plants appear by the hundreds in greenhouses every spring for Mother’s Day and Memorial Day, possibly even for Make Your Own Window Box Day!
However, the genus name “geranium” officially belongs to the hardy “cranesbill.” The plant everybody knows as annual geranium actually is “pelargonium.” Since it is translated “storksbill,” it and geranium obviously are two different birds! (The “bills” on both names refer to the plants’ pointy seed capsules.)
In the Zonals
The previously mentioned most common type of pelargoniums are the zonal hybrids (Pelargonium x hortorum) with roundish leaves, sometimes marked with non-green zones, and heads of bright flowers. They originally derived from the scarlet geranium (Pelargonium inquinans), which may explain why the classic color of those blooms was red. But it would be crossed with a variety of others, including the pink-flowered pelargoniums zonale and frutetorum, to get gardeners out of their comfort zonals and into a whole new range of colors and forms.
Reverting to Types
However, the zonals aren’t the only “annual” geraniums out there—not by a long shot. Among the other pelargoniums are the ivy-leaf hybrids, the regal or Martha Washington hybrids (Pelargonium x domesticum), such as the one pictured above, the angel (AKA pansy) hybrids, and close to 300 species varieties—including scented leaf types.
Ivy leaf hybrids derived from Pelargonium peltatum, such as the one below, boast ivy-like leaves and dangle from pots and window boxes just as ivy does. Descended from cucullatum and crispum respectively, the regal and angel types look similar to each other with pansy-like blooms and pleated leaves, but the angels usually are more petite than the Marthas.
The scented species come in a wide range of foliage shapes and fragrances, some producing showy flowers and some very tiny ones. Probably most popular is the rose geranium (Pelargonium graveolens) sometimes featured in dessert recipes and the citronella plant (Pelargonium citrosum) often used to repel mosquitoes. Most scented types are very easy to start from cuttings, since those cuttings can be mailed dry and still root.
Then, of course, there are many other species types—most native to South Africa—which never caught on as well as the previously mentioned ones did. Among those I have grown is Pelargonium myrrhifolium, with finely cut ferny foliage which doesn’t at all resemble pelargonium leaves, a species with somewhat bamboo-like stems that I've yet to identify, and the “black” geranium called sidoides.
The latter has become almost more famous as an herb than as a decorative plant, though its combination of silver leaves and finely cut dark red flowers is very classy. And even those previously mentioned common zonal geraniums come in uncommon forms, such as the rosebud type above in which the flower heads resemble nosegays of tiny roses.
In the Zones
Although usually sold as annuals, zonal pelargoniums really are tender perennials and can survive winters outdoors in USDA zones 10 and 11, the ivy leaf, regal, and angel types in zones 9 through 11, while the scenteds vary in hardiness according to type. In such warmer zones, the plants can flower almost indefinitely if not exposed to excessive heat and humidity. (Mostly native to South Africa, they prefer dry air and cool “sleeping weather” at night.) In zones where they aren’t hardy, they can be brought indoors to be enjoyed as houseplants over winter.
Or you can shake the dirt from zonal pelargonium roots and string the plants up by their “heels” in a chilly, dark basement or attic over the winter, to re-plant and re-start them in spring. I tried this once with mixed results. I've guessing I probably forgot to dampen the roots every month or so, as is generally advised! Some of the plants survived that arid period and some didn’t.
You’ll want to leave regal and angel types in their pots and outdoors until the last moment, as they flower best after receiving six weeks of short days and long nights when the temperature drops below 55 degrees but not below freezing. Scented types, on the other hand, may require a whole winter of such chilly nights to produce blooms in spring.
Although usually started from cuttings, pelargoniums are easy to raise from seed as well. Those seeds generally will sprout within 4 to 8 days if barely covered with the seed-starting mix and kept warm. The white zonal geraniums pictured above were grown from seeds which I received in a trade. I probably should have strung those up over winter instead of setting their broad shallow pot on a windowsill, because our cats had massacred the plants by spring. But, then, cats always are hard on birds!
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Photos: The photos included in the article are my own.