'', the first species of its genus to be cultivated, here shown in its native habitat in
Cape Town Various types of
Pelargonium are regular participants in flower shows and competitive events, with numerous societies devoted exclusively to their cultivation. They are easy to propagate
vegetatively from
cuttings. Zonal geraniums grow in
U.S. Department of Agriculture hardiness zones 9 through 12. Zonal geraniums are basically tropical perennials. Although they are often grown as annuals, they may overwinter in zones as cool as zone 7.
Cultivation history The first species of
Pelargonium known to be cultivated was
P. triste, a native of
South Africa. It was probably brought to the
Botanical Garden in
Leiden before 1600 on ships which had stopped at the
Cape of Good Hope. In 1631, the English gardener
John Tradescant the elder bought seeds from Rene Morin in Paris and introduced the plant to England. By 1724,
P. inquinans,
P. odoratissimum,
P. peltatum,
P. vitifolium, and
P. zonale had been introduced to Europe.
Cultivars There was little attempt at any rational grouping of
Pelargonium cultivars, the growing of which was revived in the mid-twentieth century, and the origins of many if not most were lost in obscurity. In 1916 the American botanist
Liberty Hyde Bailey (1858–1954) introduced two new terms for zonal and regal pelargoniums. Those pelargoniums which were largely derived from
P. zonale he referred to as
P. × hortorum (i.e. from the garden), while those from
P. cucullatum he named
P. × domesticum (i.e. from the home). In the late 1950s a list (the Spalding List) was produced in the United States, based on nursery listings and the 1897 list of
Henri Dauthenay. It described seven groups, listing each cultivar with the list of its originator, and in most cases a date. These were Species, Zonals, Variegated-Leaved, Domesticum (Regals), Ivy-Leaved, Scented-Leaved and Old. In the 1970s the British Pelargonium and Geranium Society produced a checklist and the Australian Geranium Society started to produce a register but it was not completed till its author, Jean Llewellyn's death in 1999. None of these were published. The most complete list in its time was the 2001 compilation by The Geraniaceae Group, which included all cultivars up to 1959. Registration of cultivars is the responsibility of the Pelargonium & Geranium Society (PAGS: formed in 2009 from the British Pelargonium and Geranium Society and the British and European Geranium Society) which administers the International Register of Pelargonium Cultivars. PAGS is the
International Cultivar Registration Authority (ICRA) of the
International Society for Horticultural Science for pelargoniums. Cultivated pelargoniums are commonly divided into six groups in addition to species pelargoniums and primary hybrids. The following list is ordered by position in the PAGS classification. Abbreviations indicate
Royal Horticultural Society usage. • A. Zonal (Z) • B. Ivy-leaved (I) • C. Regal (R) • D. Angel (A) • E. Unique (U) • F. Scented-leaved (Sc) • G. Species • H. Primary hybrids Of these, A, U and Sc groups are sometimes lumped together as Species Derived (Sppd). This term implies that they are closely related to a species from which they were derived, and do not fit into the R, I or Z groups. In addition to the primary groups, additional descriptors are used. The Royal Horticultural Society has created description codes. These include; • Cactus (Ca) • Coloured foliage (C) • Decorative (Dec) • Double (d) • Dwarf (Dw) • Dwarf Ivy-leaved (Dwl) • Frutetorum (Fr) • Miniature (Min) • Miniature Ivy-leaved (MinI) • Stellar (St) • Tulip (T) • Variegated (v) These may then be combined to form the code,
e.g. Pelargonium 'Chelsea Gem' (Z/d/v), indicating Zonal Double with variegated foliage. Crosses between groups are indicated with an ×,
e.g. Pelargonium 'Hindoo' (R × U), indicating a Regal × Unique cross.
A. Zonal pelargoniums (Pelargonium × hortorum Bailey) These are known as zonal geraniums because many have zones or patterns in the center of the leaves, together with
P. scandens and
P. frutetorum. and like other cultivars are sold in series such as 'Rocky Mountain', each of which is named after its predominant colour,
e.g. 'Rocky Mountain Orange', 'White', 'Dark Red',
etc. • (i) Basic plants – Mature plants with foliage normally exceeding in height above the rim of the pot. For exhibition these should be grown in a pot exceeding in diameter but not normally exceeding . • (ii) Dwarf plants – Smaller than basic. Mature plants with foliage more than above the rim of the pot, but not normally more than . For exhibition should be grown in a pot exceeding but not exceeding . They should not exceed 20 cm in height, grown in an 11-cm pot. • (iii) Miniature plants – Slowly growing pelargoniums. Mature plants with foliage normally less than above the rim of the pot. For exhibition should be grown in a pot not exceeding . They should not exceed 12.5 cm in height, grown in a 9-cm pot. • (iv) Micro-miniature plants – Smaller and more slowly growing than miniature pelargoniums. Mature plants with foliage normally less than above the rim of the pot. They should not exceed 7.5 cm in height, grown in a 6-cm pot. Usually no separate classes for these in exhibition and will therefore normally be shown as Miniature Zonals. • (v) Deacon varieties –Genetic hybrid similar to a large Dwarf. For exhibition (when shown in a separate class), usually grown in a pot not exceeding , otherwise as for Dwarf Zonals. • (vi) Stellar varieties – A relatively modern genetic hybrid originating from the work done by the Australian hybridiser Ted Both in the late 1950s and 1960s from crosses between Australian species and Zonal types. Easily identifiable by their distinctive half-star-shaped leaves and slim-petalled blooms which create an impression of being star shaped (or five fingered). Single varieties tend to have larger elongated triangular petals whereas doubles tend to have thin feathered petals that are tightly packed together. For exhibition purposes there is a separate class for 'Stellar' varieties, but being Zonals could be shown in an open class for Basic, Dwarf or Miniature Zonals (unless otherwise stated). Also known as "The Five-fingered Geraniums", "Staphysagroides", "Both’s Staphs", "Both’s Hybrid Staphs", "Fingered Flowers" and "Bodey’s Formosum Hybrids". • (vii) Zonartic hybrids – Zonartic pelargoniums are a group of hybrids bred by Australian horticulturist Cliff Blackman. Hybridisation to establish this group began in 1985 through crosses between zonal pelargoniums (Pelargonium × hortorum) and the wild species Pelargonium articulatum. The name “Zonartic” derives from zonal and articulatum, reflecting this genetic combination. Blackman’s breeding programme produced a distinctive line of pelargoniums noted for their large, luminous flowers and for his effort to develop a true yellow pelargonium. Since then, Zonartic breeding has spread internationally, with active hybridisers in the United Kingdom, Sweden, Russia, and other countries. Breeders often identify their hybrids through a prefix; for example, Blackman used the prefix ‘Lara’ for his cultivars. Fancy-leaf zonal pelargoniums – besides having green leaves with or without zoning, this group also have variable coloured foliage that is sometimes used in classifying for exhibition purposes,
e.g. 'Bicolour', 'Tricolour', 'Bronze' or 'Gold'. Other foliage types are: 'Black' or 'Butterfly'. There are an increasing number of these plants with showy blooms; • (a) Bicolour – includes those with white or cream veined leaves or those with two distinct colours with clearly defined edges, other than the basic zone. • (b) Tricolour – (May be Silver Tricolour (usually called a Silver Leaf) or a Gold Tricolour). • (i) Gold Tricolour – Leaves of many colours including red and gold, but usually with clearly defined edges of golden yellow and having a leaf zone, usually red or bronze, that overlays two or more of the other distinct leaf colours, so that the zone itself appears as two or more distinct colours. • (ii) Silver Tricolour or Silver Leaf – These tend to resemble a normal bi-colour leaf plant with two distinct colours usually of green and pale cream or white; the third colour is usually made up of bronze zoning. When this zoning overlays the green part of the leaf it is deemed to represent a silver colour. • (c) Bronze Leaved – Leaves of Green or Golden/Green with a heavy bronze or chestnut coloured centre zone which is known as a medallion. For exhibition purposes, when exhibited in specific ‘Bronze’ Leaf class – Must have over 50% of leaf surface bronze coloured. The dwarf plant ‘Overchurch’ which has a heavy bronze medallion. • (d) Gold Leaved – Leaves coloured golden/yellow or green/yellow but not showing a tendency to green. For exhibition purposes, when exhibited in specific ‘Gold’ Leaf class – Must have over 50% of leaf surface gold coloured. • (e) Black Leaved – Leaves coloured black, purple-black or with distinct large dark zones or centre markings on green. • (f) Butterfly Leaved – Leaves with a butterfly marking of distinct tone or hue in centre of leaf. This can be encompassed in many of the coloured leaf varieties. Zonal pelargoniums have many flower types, as follows: • (a) Single flowered (S) – each flower pip normally having no more than five petals. This is the standard flower set for all Pelargoniums. • (b) Semi-double flowered (SD) – each flower pip normally having between six and nine petals. • (c) Double flowered (D)– each flower pip composed of more than nine petals (i.e. double the standard flower set) but not ‘hearted’ like the bud of a rose,
e.g. the dwarf ‘Dovepoint’ which has full double blooms. • (d) Rosebud (or noisette) flowered – each bloom fully double and ‘hearted’. The middle petals are so numerous that they remain unopened like the bud of a rose. • (e) Tulip flowered – having semi-double blooms that never fully open. The large cup shaped petals open just sufficiently to resemble a miniature tulip. • (f) Bird's-egg group – having blooms with petals that have spots in a darker shade than the base colour, like many birds eggs. • (g) Speckled flowered group – having petals that are marked with splashes and flecks of another colour,
e.g. ‘Vectis Embers’. • (h) Quilled (or cactus-flowered group, or poinsettia in US) – having petals twisted and furled like a quill. “Zonquil” pelargoniums result from a cross between Zonal pelargonium cultivars and
P. quinquelobatum.
B. Ivy-leaved pelargoniums (derived from Pelargonium peltatum) '' (Ivy-leaved) Also known as "ivy geraniums". Usually of lax growth (trailing), mainly due to the long thin stems, with thick, waxy ivy-shaped stiff fleshy evergreen leaves developed by the species
P. peltatum to retain moisture during periods of drought. Much used for hanging pots, tubs and basket cultivation. In the UK the bulbous double-headed types are preferred whilst on the European continent the balcon single types for large-scale hanging floral displays are favoured. Ivy-leaved pelargoniums embrace all such growth size types including small-leaved varieties and genetic hybrid crosses, which display little or no zonal characteristics. May have bicolour leaves and may have flowers that are single, double or rosette. Ivy pelargoniums are often sold as series such as 'Great Balls of Fire', in a variety of colours such as 'Great Balls of Fire Burgundy'. Additional descriptive terms include; • Hybrid Ivy — the result of ivy × zonal crosses, but still more closely resemble ivy-leaved pelargoniums. • Fancy leaf — leaves with marked color variation, together with or other than green. • Miniature — miniature leaves and flowers, stems with short nodes, and compact growth.
e.g. 'Sugar Baby' listed as Dwarf Ivy (DwI) by RHS.
C. Regal pelargoniums (Pelargonium × domesticum Bailey) These are large bush-type
floriferous evergreen pelargoniums. In addition to "Regals" they are also known as “Show Pelargoniums”. In the US they are often known as the "Martha Washington" or "Lady Washington" pelargoniums. They are grown primarily for the beauty and richness of their flower heads, which are large. Most of those cultivars grown currently are the result of hybridization over the last 50 years. They are very short-jointed and compact, which results in their requiring very little work in order to create a floriforous and well-rounded plant. Flowers are single, rarely double, in mauve, pink, purple or white. They have rounded, sometimes lobed or partially toothed (serrated) leaves, unlike the Zonal groups, without any type of zoning. Additional descriptive terms include; • Fancy leaf – Leaves with marked variations in colour • Decorative pelargoniums (Decoratives) – Descendants of older, less compact, smaller-flowered varieties that are more suited to outdoor conditions. These have smaller flowers than Regal, but are otherwise similar.
e.g. 'Royal Ascot' • Miniature – Flowers and leaves similar to Regal, but miniature in form, with compact growth. Other terms include "Pansy Geraniums" or "Pansy Pelargoniums".
e.g. 'Lara Susan' • Oriental pelargoniums – The result of crosses between Regals and members of the Angel group (see below). Some have bicolour foliage.
D. Angel pelargoniums (derived from Pelargonium crispum) Angel pelargoniums are similar to Regal pelargoniums but more closely resemble
P. crispum in leaf shape and growth habit. The majority of Angel cultivars originate from a cross between
P. crispum and a Regal variety in the early part of the 20th century. Angels have grown in popularity in the last 30 years or so due mainly to an explosion of new varieties being released by specialist nurseries resulting from the work done by dedicated amateur hybridisers. These hybrisers have managed to obtain many new flower colour breaks and tighter growth habits resulting in plants suitable for all sorts of situations. Angels basically have the appearance of a small Regal with small serrated leaves and much smaller flowers and are more compact and bushy. The group extends to include similar small-leaved and -flowered types but usually with
P. crispum in their parentage. They are mostly upright bush-type plants but there are some lax varieties that can be used for basket or hanging pot cultivation. Often called "pansy-faced" in the US. Some varieties have bicolour foliage. Other terms include ‘Langley-Smith Hybrids’.
E. Unique pelargoniums (derived from Pelargonium fulgidum) Unique in sense of not fitting into any of the above categories. The parentage of Unique pelargoniums is confused and obscure. One theory being a derivation from
P. fulgidum, but a derivation from an older cultivar 'Old Unique', also known as or 'Rollinson’s Crimson', in the mid-19th century is also claimed. Unique pelargoniums resemble upright Scented Leaf pelargoniums in being shrubby and woody evergreens. They have distinctly scented leaves, and small flowers with blotched and feathered petals. They may have bicolour foliage. Some types, popularly known in the hobby as hybrid Uniques, have been crossed with Regal pelargoniums and, as a result of this cross, are much more floriferous. ; Cultivar: • Fiery-flowered Stork's-bill, Scarlet Unique Scented Geranium (
P. ×
ignescens) – a
P. fulgidum hybrid
F. Scented-leaved pelargoniums '' (scented leaf) Shrubby evergreen perennials grown chiefly for their fragrance, may be species or cultivars but all must have a clear and distinct scented foliage. Scent is emitted when the leaves are touched or bruised with some scents aromatic, others pungent and in a few cases, quite unpleasant. Several of the scented leaved pelargoniums are grown for the oil
geraniol, which is extracted from the leaves and is an essential oil much used commercially in perfumery. The scent of some species growing in their natural habitat, acts as a deterrent to grazing animals who appear to dislike the emitted scent. Conversely, it also attracts other insect life to visit the bloom and pollinate the plant. The scented leaves can be used for potpourri and they also have a use as flavourings in cooking. Occasionally scented types can be found in some of the other groups mentioned; for example, the Angels, having
P. crispum in their genetic makeup, can often have a strong citrus scent. Leaves are lobed, toothed, incised or variegated. Growth habit is very variable, but the flowers are less prominent than other groups, and most closely resemble the species they originated from. These include: '' 'Fair Ellen' (scented leaf) '' (scented leaf) • Almond -
Pelargonium quercifolium • Apple -
Pelargonium odoratissimum • Apple -
Pelargonium cordifolium • Apple/Mint -
Pelargonium album • Apricot/Lemon -
Pelargonium scabrum • Balsam -
Pelargonium panduriforme • Camphor -
Pelargonium betulinum • Celery -
Pelargonium ionidiflorum • Cinnamon - ''Pelargonium 'Ardwyck Cinnamon''' • Coconut -
Pelargonium grossalarioides (
Pelargonium parriflorum) • Eau de Cologne - ''Pelargonium 'Brilliantine''' • Eucalyptus - ''Pelargonium 'Secret Love''' • Grapefruit - ''Pelargonium 'Poquita''' • Ginger - ''Pelargonium 'Torrento''' or 'Cola Bottles' which is a variety of
Pelargonium x
nervosum • Hazelnut - ''Pelargonium 'Odorata Hazelnut'' • Lavender - ''Pelargonium 'Lavender Lindy''' • Lemon -
Pelargonium crispum • Lemon -
Pelargonium citronellum (Synonym -
Pelargonium 'Mabel Grey') • Lemon Balm -
Pelargonium x melissinum • Lime -
Pelargonium x nervosum • Myrrh -
Pelargonium myrrhifolium • Nutmeg -
Pelargonium x fragrans • Old Spice -
Variety of Pelargonium x fragrans • Orange -
Pelargonium x citriodorum (Synonym -
Pelargonium 'Prince of Orange') • Peach - ''Pelargonium 'Peaches and Cream''' • Peppermint -
Pelargonium tomentosum • Pine -
Pelargonium denticulatum • Pineapple - ''Pelargonium 'Brilliant''' • Raspberry - ''Pelargonium 'Red Raspberry''' • Rose -
Pelargonium graveolens (Synonym -
Pelargonium roseum) • Rose -
Pelargonium capitatum • Rose -
Pelargonium radens • Southernwood -
Pelargonium abrotanifolium • Spicy -
Pelargonium exstipulatum • Strawberry -
Pelargonium x scarboroviae ; Cultivars: • 'Attar of Roses' - a cultivar of
P. capitatum • 'Crowfoot Rose' - a cultivar of
P. radens • 'Dr. Livingston' - a cultivar of
P. radens • 'Grey Lady Plymouth' - a cultivar of
P. graveolens • 'Prince Rupert' - a cultivar of
P. crispum G. Species pelargoniums The species are the forefathers of all the cultivar groups listed above. In general, the definition of a species is that it breeds true, and is to be found doing this in the "wild". Species pelargoniums have a large diversity of characteristics in habit, shape, size and colour, which probably accounts for them having retained their popularity for more than 300 years.
H. Primary hybrids A primary hybrid is recognised as being the resultant plant from a first-time cross between two different known species. Examples are
P. ×
ardens – from
P. lobatum ×
P. fulgidum (1810).
P. ×
glauciifolium – from
P. gibbosum ×
P. lobatum (1822). Primary hybrids are usually, but not always, sterile.
List of AGM pelargoniums The following is a selection of pelargoniums which have gained the
Royal Horticultural Society's
Award of Garden Merit: • 'Attar of Roses' (rose scented leaves, pink flowers) • 'Citriodorum' (lemon scented leaves, rose pink flowers) • 'Dolly Varden' (variegated leaves, scarlet flowers) • 'Frank Headley' (cream vareigated leaves, salmon pink flowers) • 'Fringed Aztec' (white & purple fringed flowers) • 'Gemstone' (scented leaves, pink flowers) • 'Grace Thomas' (lemon scented leaves, pale pink flowers) • 'Joy' (pink & white frilled flowers) • 'Lady Plymouth' (
P. graveolens variegata – small mauve flowers) • 'Lara Candy Dancer' (scented leaves, pale mauve flowers) • 'Lara Starshine' (aromatic leaves, lilac flowers) • 'L'Élégante' (ivy-leaved, trailing, white and purple flowers) • 'Mabel Grey' (lemon-scented leaves, mauve flowers) • 'Mrs Quilter' (bronze leaves, salmon pink flowers) • 'Radula' (lemon & rose scented leaves, pink & purple flowers) • 'Royal Oak' (balsam scented leaves, mauve flowers) • 'Spanish Angel' (lilac & magenta flowers) • 'Sweet Mimosa' (balsam-scented leaves, pale pink flowers) • 'Tip Top Duet' (pink & wine-red flowers) • 'Voodoo' (crimson & black flowers) •
P. tomentosum (peppermint-scented leaves, small white flowers) ==Uses==