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Scientific: Pelargonium species (a complex grouping of 5 species: P. capitatum, P. crispum, P. denticulatum, P. tomentosum, and P. zonale)
Common: pelargonium, garden geranium, ivy geranium, scented geranium, zonal geranium ---- let's stop the confusion and call these gardens staples "pelargoniums" instead of "geraniums".
Family: Geraniaceae
Origin: South Africa

Pronounciation: Pel-ar-GO-knee-um SPEE-sheez

Hardiness zones
Sunset
All zones (cool season annual in desert locations, warm season annual in temperate climates with winter freezes, and perennials along coastal California regions, especially central and southern California)
USDA All zones

Landscape Use: Flower of landscape border accent, cool season landscape flower bed annual, container plant or hanging basket for patios, herb, cut flowers. In Mediterranean climates such as southern and central California, pelargoniums are a herbaceous, perennial landscape accent subshrub that can grow for decades forming thick clumps.

Form & Character: Prostrate and spreading, trailing to upright and bushy, soft, engaging, informal.

Growth Habit: Evergreen, herbaceous annual to perennial, depending on species and climo-geographic location. Some species are prostrate, trailing and spreading. Other species are basally clumping, stiffly upright and brittle to 4 feet in height with near equal spread.

Foliage/Texture: Simple alternate leaves with elongated petioles. The leaf lamina are rounded to sometimes lobed with palmate veination, some are scented, some are pubescent, some are lightly or darkly patterned, petioles can also be pubescent; medium texture.

Flowers & Fruits: Flowers heavily clustered in an umbel configuration on long stalks that are occassionally branched, five-petaled with a single symmetry occurring in many colors ranging from white, pink, salmon, deep rose red, to purple. Double and multi-colored flowered variants occur. Fruits are dry and breaks up into five ellipsoid parts, each with a corkscrew awn at the top. This beak-like column enables seed to be "thrown" when fruit are ripe.

Seasonal Color: Flowers most heavily in winter and spring.

Temperature: In Phoenix, pelargoniums are quite frost and freeze intolerant and will experience winter chill injury (foliage color turns red and/or purple) if nighttime temperatures fall below 40oF, but tolerates summer heat to 105 to 110oF.

Light: Full sun to partial shade.

Soil: Extremely tolerant of all soil textures, seems to do better in slightly to moderate alkaline soils.

Watering: Give water regularly in Phoenix, otherwise tolerates drought especially well in Mediterranean climates such as Santa Barbara, Los Angeles and San Diego.

Pruning: None

Propagation: ABSOLUTELY EASY!! Semi-hardened softwood cuttings can root quickly in most any rooting substrate, even Grandma's vase filled with water on the kitchen window sill. One can also stick semi-hardened softwood cuttings directly into soil outdoors in Phoenix and southern California in winter and they will quickly form adventitious roots. Pelargonium is also propagated by seed and by division of perennial clumps.

Disease and Pests: Few disease and pest problems in dry climates such as spittle bug. In wetter climates, many foliar and root pathogens such as botrytis, leaf rust, pythium, phytophthora, bacterial blight.

Additional comments: Present day garden pelargoniums are prolific bloomers and are hybrids derived from several species including Perlargonium inquinans, P. zonale, and P. hortorum that are all native to South Africa. These species were introduced into Europe in the early 18th century. The are all simple to grow, carefree, and most commonly used in Phoenix as a cool season bedding plant in flower beds and container pots. There are so many cultivated varieties of Pelargonium! Pelargoniums are much beloved around the world like roses.

Some taxonomic guidance: Garden pot plants sold at retail nurseries and garden centers that are labeled "ivy geranium", "scented geranium" and "zonal geranium" are actually three different species of Pelargonium - so why not instead call them "ivy pelargonium", "scented pelargonium" and "zonal pelargonium"? Geranium is a genus of different species that do well as perennials in temperate-zone climates with freezing winter temperatures.