They are the group of Pelargonium cultivars, with leaves marked with a brown annular zone and inflorescence in the form of large balls of tight flowers, usually red, pink, or white.

These are the most common geraniums of garden centers and florists, sold in pots for windowsills and balconies or planted in flowerbeds.

The specific epithet hortorum is a genitive plural form of the Latin "hortus" ("garden") and therefore corresponds to "horticultural".

The name was created by the American botanist Liberty Hyde Bailey who in 1914, writes "The large number of forms of the common geranium, derives from the variation and probably the crossing of P. zonale and P. inquinans (and possibly others) during more than a century of careful selections".

Currently, most gardeners, amateur or professional, know perfectly well that the geraniums that decorate the balconies are Pelargonium but they are reluctant to use the term they find too pedantic.

But this name will only be widely accepted in the 19th century, and in the meantime varieties and horticultural hybrids of these species were a great success with gardeners, they kept the habit they had taken to call them "geraniums", a term that was unambiguously in context.

It was only during the second half of the 18th century that the foundations of hybridization and floral biology began to be established through the work of two remarkable German experimenter Kurt Polycarp Joachim Sprengel (1750–1816).

In 1793, Sprengel established that most hermaphroditic flowers could not be fertilized by their own pollen because their reproductive organs did not reach maturity at the same time (as is the case with Geraniaceae).

When he died in 1780, in the inventory of his plants, there is a Fothergill's geranium, later described as having a large ball of flowers and zoned leaves and considered as such one of the first Pelargonium zonal group.

At the beginning of the century, few hybridizations in the zonal group were carried out, as far as can be known because the horticulturists reused the same denomination for different plants and did not indicate the kinship of their obtaining.

The exchange of varieties between France and England made it possible to enrich the collections on both sides of the English Channel.

During major exhibitions where growers present their latest creations, competitions are organized to award gold medals to outstanding cultivars.

The inflorescence is carried by a long rigid peduncle, starting from the armpit of the upper leaves, so that the flowered head stands out clearly above the foliage.