Care for Your Garden
I have added an unusual new plant for my garden, a Pelargonium appendiculatum (no common name in English). I’ll provide information about this plant, but to begin let’s look into its relatives.
The Pelargonium appendiculata is noted for its caudex (succulent root) so it could be included in a succulent plant bed. (Tom Karwin)
This plant is a member of the Geranium plant family (Geraniaceae), which includes seven genera. The most familiar are Geranium (430 species, mostly native to the eastern Mediterranean region), Pelargonium (280 species, mostly from southern Africa), and Erodium (80 species from northern Africa).
These genera are popular selections for gardeners because of the wide range of sizes, forms, textures and blossoms. They are also favored by plant hybridizers, who have created numerous cultivars for various garden situations. All are welcome in the Monterey Bay area’s gardens.
By the way, one of the smaller genera in the Geranium family is the Roundleaf Stork’s Bill (California macrophylla), with a single species that is native to the southwestern United States. It grows just one inch high, making it curious but not particularly desirable.
The Genarium plant family has an unusual history of entanglement between two of its genera: Geranium and Pelargonium. Taxonomist Carl Linnaeus regarded both within the same genus, but, in 1789, Charles L’Heritier concluded they were separate genera. Botanists have retained that distinction, but gardeners often confuse them.
Geraniums and Pelargoniums are similar in several ways, but they have differences. Their common names, Cranesbill for Geraniums and Storksbill for Pelargoniums, suggest their similarities. Both common names refer to the plants’ seedpods, which resemble bird beaks but with subtle differences, but few gardeners could describe the differences between crane and stork bills.
Pelargoniums are frost-tender plants (not a problem in the Monterey Bay area’s gardens), while Geraniums do so well during cold weather they are called “Hardy Geraniums.”
Pelargonium flowers have two upper petals and three lower petals, in bilateral symmetry, Geranium flowers, by comparison, have five petals, arranged in radial symmetry. Some Pelargonium hybrids, however, have blossoms that look more like Geranium blossoms, so they might encourage confusion of the genera.
Pelargonium blossoms are typically grouped in umbels (with equal stalks from a common center, while Geranium blossoms occur in cymes (central stem with a single flower followed by a cluster of later flowers on lateral stems). Once you compare umbels and cymes in reality, their differences will be clear. It might help to think of umbels as umbrellas.
Pelargonium species and cultivars are the more widely grown garden selections. There’s a good possibility that the plants you call Geraniums are really Pelargoniums.
My newly acquired Pelargonium appendicular is a tuberous plant (a geophyte) that has a short stem with interesting gray leaves described as “irregularly incised and feathery.” Its silky leaves and unusual stipules (small leaflike appendages to a leaf) make it different from all other Pelargonium species. The species name refers to the appended stipules.
This plant grows only about 12 inches high and in time will form an 18-inch wide clump. Its small rose-colored blossoms rise a little above the foliage, which is the plant’s most important feature.
Some other examples in my garden:
Ivy Geranium (Pelargonium peltatum) has leaves similar to ivy (Hedera) leaves. This is a scrambling perennial plant with blossoms that range from white to mauve. This plant is popular in hanging baskets, but my specimen is reaching into adjacent plants. I need to move it to the South African flower bed.
Kidney-Leaved Geranium (Pelargonium reniforme). This is an evergreen, small, upright perennial shrub with tuberous roots and foliage that mounds to about 12 inches high and wide. Its flowers vary from pink to magenta with a darker spot and stripes on the upper two petals.
The Kidney-leaved Geranium (Pelargonium reniforme) has rounded dark green leaves with frilly edges, and pink umbels. (Tom Karwin)
Madeira Island Geranium (Geranium maderense). This giant plant (the largest in the Geranium family) has attractive fern-like foliage that grows to three feet high and wide, and a massive inflorescence of one-inch wide mauve-pink flowers with dark centers rising to five feet. The plant blossoms biennially, and the foliage provides interest during alternate years.
Biokovo Cranesbill (Geranium x cantabrigiense ‘Biokovo), which is a natural hybrid discovered in Croatia’s Biokova Mountains. Its trailing stems form a foliage carpet 12 inches high and 18 inches wide. It produces long-lasting white-to-pink one-inch blossoms from late spring to mid-summer.
I acquired this Giant Geranium at the Santa Cruz Garden Exchange, years ago. It has flourished and produced many seedlings to share with other gardeners. (Tom Karwin)
Advance Your Gardening Knowledge
A fine resource to learn more about Geraniums, Pelargoniums, and Erodiums is the website geraniaceae.com, based on the Marin County, California plant nursery that Robin Parer has managed since 1983.
This is a well-organized website with authoritative information about an enormous range of plants and opportunities to purchase plants to add to your own garden.
For more about Parer and her nursery, browse to https://tinyurl.com/yc2nzudn.
Side note: My new Pelargonium appendiculum was grown by the University of California, Davis’s Botanical Conservatory, and made available during a talk by the Conservatory’s Manager Ernesto Sandoval at a meeting of the Monterey Bay Area Cactus & Succulent Society. This plant is not listed on Robin Parer’s nursery website! Thanks, Ernesto, for enabling me to add a rarity to my garden.
Enjoy your garden!
Tom Karwin is a past president of Friends of the UC Santa Cruz Arboretum and the Monterey Bay Iris Society, a past president and Lifetime Member of the Monterey Bay Area Cactus & Succulent Society, and a Lifetime UC Master Gardener (Certified 19992009). He is now a board member of the Santa Cruz Hostel Society, and active with the Pacific Horticultural Society. To view daily photos from his garden, https://www.facebook.com/ongardeningcom-566511763375123/. For garden coaching info and an archive of previous On Gardening columns, visit http://ongardening.com.
This plant is a reliable groundcover, with attractive foliage and long-lasting blossoms. (Tom Karwin)