Recently, I’ve dug a lot of geraniums of my garden because they had grown exuberantly in the wrong place. I will describe these interlopers later in this column.
Plants that grow where they are not wanted have been called “weeds,” but that’s not an appropriate name for these plants because they are garden-worthy in all respects. A better description would be “prolific,” which is a desirable trait for garden plants.
My project to manage geraniums in my garden prompts a brief overview of the Geranium family (Geraniaceae),
Let’s first review the confusion over genus names in this family. Today, we understand that the Geraniaceae includes three principal genera: geranium, pelargonium, and erodium. During the 1750s and 1750s, when Carl Linnaeus was naming plants, he included all three of these genera as geranium. In 1789, another botanist concluded that geranium and pelargonium were, in fact, different genera. Others later decided that erodium was also a separate genus. Despite this long-standing agreement on these names, many gardeners still call pelargoniums “geraniums,” although they are quite different, each with desirable characteristics.
The name “geranium” refers to the crane, while the name “pelargonium’ refers to the stork, but I actually do not find that helpful.
The true geraniums are often called “wild,” although many popular varieties are hybrids, or “hardy,” even though some geranium species don’t do well in winter. (Pelargoniums are not winter-hardy.)
The genus Geranium includes 422 species of annual, biennial and perennial plants. Most geraniums are native to the eastern part of the Mediterranean region, but they are found throughout the temperate regions of the world and the mountains of the tropics.
An excellent guide to this family of plants is the website Geraniaceae, which is maintained by Robin Parer, a very knowledgeable person in Marin County.
The site describes plants within the three principal genera of the Geraniaceae. It lists many species of Geraniums in the following groups (with numbers of species): Annuals (6); Borders & Bedding (169); Ground Covers (86); Rock Gardens & Containers (39); Scramblers & Crawlers (23); and Shade (83).
The geranium I dug out of my garden is G. x cantabrigiense. The species name is based on the Latin name for Cambridge, England, where the hybrid was developed. My plant is the cultivar ‘Biokovo’, which is a natural hybrid discovered in Croatia’s Biokovo Mountains. The Perennial Plant Association named this plant 2015 Perennial Plant of the Year. It is an excellent ground cover that grows up to a foot high and displays white blossoms with a pink throat and prominent pink stamens. The blossoms generally open in late spring and continue into the fall, but have appeared early this year.
This plant had spread in several parts of my garden. I had yards and yards of it! I removed a 3’ x 30’ bed that amounted to perhaps 25 percent of the total so plenty continues to grace the landscape and will need future control. I removed these plants because they were growing in an area I had designated for natives of California and Mexico; I have planted this area with seeds of two varieties of the Four O-Clock (Mirabilis jalapa), which is a Mexican native and another vigorous grower.
Another geranium in my garden is G. canescens, which is a larger, relatively rare South African species that has been growing in my garden for only seven months. The species name means “to become grey, to become old,” but the plant, which is luscious green and doesn’t appear to deserve that name. It has large, deeply lobed leaves, and will display pink flowers later in the spring.
To explore the garden possibilities for the geranium, visit Geranaiceae.com or talk to Robin Parer in person at the San Francisco Flower & Garden Show, which returns to the San Francisco’s Cow Palace, April 4–8, (www.sfgardenshow.com/).
Hardy geraniums can be fine additions to the garden landscape.