Much more about...ERODIUMS ( or is that Erodia?)

     After the Erodium grouping that I entered in a recent Columbus Bonsai Society annual recent show attracted some favorable comment, our program chair Ken Schultz, ever alert for a meeting topic, asked me if I would be interested in doing a program about these delightful little plants. Part of his motivation may have come from the comments of one show goer who had trouble keeping Erodium alive.

Seen at a nursery in a standard grow pot, Erodium shows off it's
pretty blossoms, but the potential for bonsai may not be apparent.

     Every bonsai grower has at least one kryptonite species-a type of plant that they just can't keep alive even though, other growers, web site and guide book says it is easy to grow. I certainly empathize with any grower who feel a particular species of plant has turned against them. But it is a surprise to hear an Erodium mentioned as the trouble maker. Most reports of this plant are that it is a tough, adaptable customer the performs well under many varied conditions.
     Erodiums are part of the family Geraniaceae, which also includes Geraniums and Pelargoniums. This kinship is evident in leaf shape and general form. Linneaus grouped all three of these now separate genera in one genus, Pelargonium. They were later given their separate classification based on the number of stamens in their blossoms. This change in nomenclature is the reason that those popular red flowered plants that invade garden centers and front porches every spring are commonly called Geraniums, though they are properly grouped as a Pelargonium.
     There are about 60 species of Erodium, native mainly to the Mediteranian basin and western Asia. They are often given the common names stork's bill , heron's bill or crane's bill, because their long, narrowly pointed seed pods resemble a bird's beak. This resemblance is echoed in the scientific names each of the related genera bears: Geranium for the crane ( geranos in Greek), Pelargonium (Greek for stork) and the heron (erodios). From my point of view these three bird have what seem to be identical beaks, and this similarity may account for the fact that the three common names are used interchangeably for members of all three genera.
     This indiscriminate name use reflects how similar in appearance most of these plants are, and how closely related. The plant we use for bonsai is frequently sold as E. reichardii  and also as E. variable. The name E. variabile was suggested in 1980 by Dr. Alan Leslie of the Royal Horticultural Society to describe an intermediate species between E. reichardii(synonymous with E. chamaedryoides) native to the Pyranees of Northern Spain, with E. corsicum native to Corsica. Though attempts to cross these species intentionally failed, apparently spontaneous hybridizations had been occurring in alpine gardens for some while before conscious selections were made for cultivation.

Erodium in various stages of development,as
as grown by Ken Huth, Ken's World of Bonsai.
Ken is well know for recycling beverage cans for grow
pots-waste not, want not.

     Soon after the hybrid status for E. variabile was described, Dr. Leslie's fellow enthusiasts began expressing doubts that it was a hybrid at all, but merely a variant-leafed form of E. reichardii. The issue was eventually brought before the Royal Horticultural Societies Advisory Board for Nomenclature & Taxonomy, and it was decided to spring for the cost of DNA investigation, which found that Dr. Leslie's surmise of spontaneous hybridization was indeed the case.
Although the question of identity is a tough one to unravel, it may not matter much since the plants in question require basically identical care and culture. Outside of bonsai, Erodium are popular as rock garden plants, and given their origins in the rocky hills along the Mediterranean Sea, that should be no surprise. Mediterranean climates are not just found around ˜The Med" but the South African Cape, Southern and Western Australia, Central Chile, and much of California are considered Mediterranean climates as well. This is an area where the familiar Rosemary , Lavender, Olive and Cypress thrive, and plants from this area are adapted to deal with a cool wet winter and dry hot summer. Many plants from the area go dormant to avoid summer heat rather than winter cold.
     I think this is reflected in the growth habits I've seen my Erodium demonstrate. Though they are probably borderline hardy, I have always taken them indoors over winter. They live from October to April under shop lights in the basement, then find a place on the bonsai benches over the summer. Outdoors, the small pots are grouped in sand trays, which means they can stand the all day sun they are situated in. The plants stay a healthy green and bloom freely over the summer, but the intense sun seems to encourage such compact growth (leaves and leaf stems are very small) that they don’t seem to grow much. I am convinced that not only are the leaf structures kept small by the sun, the internodal length-the space between each leach stem is kept small too, an ideal situation for maintaining a bonsai, though it can make for a lengthy process if you are trying to develop one.

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     I think this adaptation to a hot summer and cool winter makes it easy to take Erodium inside and use that winter break for real development as shohin bonsai. Erodium really show the result of what could be called the bonsai effect that is, being dwarfed by pot culture. In that respect Erodium really are ideal bonsai material, in that they already have a form and habit that are small in scale, and will reduce even further in bonsai culture.

The Erodium fact sheet

Scientific name/common name: Erodium reichardii ,Heron’s bill, also crane’s bill, stork’s bill, baby geranium, alpine geranium.

Native region: Pyrenees mountains of Southern Spain, and Mediterranean islands. In cultivation world wide.

Form and habit: Slow growing, mound forming perennial, growing 2-4 inches tall and eventually reaching 12 inch spread. Leaves are bright green, slightly fuzzy and basically oval, with slightly lobed of scalloped edges. Blooms year round in cultivation, plants are dioecious (separate male and female plants).

Care:     Soil-Prefers a moist but well drained soil, ideal mix should balance organic matter with grit, also prefers alkaline soil.

                Light-Can grow in bright shade to full sun.  Full sun will yield most compact growth and very short leaf stems desirable in bonsai,

                Moisture-Requires good drainage but moist conditions, care should be taken to assure that small pots do not dry out.  These plants are somewhat drought tolerant but caution is always advised. A sand tray or pot-in-pot technique will help moderate water demands in small containers.

                Fertilizer-Not a heavy feeder, use a balanced fertilizer. A low nitrogen, higher phosphorus feed will often bring on a wave of blooms.

                Propagation-Strikes easily from stem and root cuttings. Root cuttings should be completely buried in soil and kept moist, stem cuttings should be trimmed of all but a few leaves.  Even very small stem sections will root.

Recommended soil mix: Note that no sand or gravel is included; I feel that in small pots all soil ingredients should hold some moisture.

                                                Mulch fines

                                                Turface fines

                                                Coffee grounds

                                                Ground limestone

                                                Vermiculite

                                                “Moisture control” potting soil