Pelargonium odoratissimum
(apple geranium)

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Identity

Preferred Scientific Name

• Pelargonium odoratissimum (L.) L'Hér.

Preferred Common Name

• apple geranium

Other Scientific Names

• Geranium odoratissimum L.

International Common Names

• English: nutmeg geranium; sweet-scent pelargonium
• Spanish: geranio de rosa; geranio malva; pelargonio
• French: geranium; geranium-rosat; pelargonium citronne

Local Common Names

• Germany: Apfelduft-pelargonie; Rosenstorchschnabel; Zitronenpelargonie
• Italy: geranio incense; geranio odoroso; malva d’Egitto; marvetta odorata
• Korea, Republic of: hyangkkotauk; yangauk
• Puerto Rico: aroma; geranio de olor; malvarrosa
• Russian Federation: pelargonija duschistaja

Summary of Invasiveness

P. odoratissimum, commonly called ‘apple geranium’, is a flowering plant cultivated around the world as a popular ornamental and for its sweet leaves, aromatic scent and essential oil. The species is reported to have escaped from cultivation in Puerto Rico (Liogier and Martorell, 2000) and was listed as “garden thug, naturalised, weed” in the Global Compendium of Weeds (Randall, 2012). Little data, however, is available on the invasiveness of this species; while it can reproduce by both seeds and cuttings and has a history of repeated introduction outside of its native South African range, the plant does not appear to be a high-risk species at this time.

Taxonomic Tree

• Domain: Eukaryota
•     Kingdom: Plantae
•         Phylum: Spermatophyta
•             Subphylum: Angiospermae
•                 Class: Dicotyledonae
•                     Order: Geraniales
•                         Family: Geraniaceae
•                             Genus: Pelargonium
•                                 Species: Pelargonium odoratissimum

Notes on Taxonomy and Nomenclature

There has been much confusion in the literature surrounding the genera of Pelargonium and Geranium. The genus Geranium was originally described by Linnaeus in 1753 but was then divided into Pelargonium and Geranium by Charles L’Héritier in 1789, and many species from both genera have retained the name ‘geranium’ in their vernacular names. Further, many cultivars and varieties exist, many with similar variety names to other species. The genus name Pelargonium derives from the Greek word ‘pelargos’, meaning ‘stork’, in reference to the beak-like shape of the fruit, which has also resulted in the genus being called the ‘stork’s bill’ genus (Stearn, 1992).

In the case of P. odoratissimum, ‘apple geranium’, for example, Lis-Balchin (2002) argues that this species has probably been confused with an aromatic cultivar of P. graveolens, and it is the P. graveolens cultivar that produces geranium essential oil, not the actual species P. odoratissimum as “misquoted” by Knuth (1912) and repeated in subsequent literature.Seidemann (2005), however, notes that ‘the true species is apple-scented’ and Hanelt et al. (2001), USDA-ARS (2014) and other sources used for this datasheet include the species’ usefulness as a source of essential oil. The specific name odoratissimum, most fragrant, refers to the sweet smell of the leaves (SANBI, 2014). The species is classified under the section Cortusinaof the genusPelargonium.

Description

SANBI (2014) says: P. odoratissimum is a perennial and relatively flat-growing shrublet with a short thick main stem with extensive herbaceous flowering branches which are 60 cm in length. The plant rarely grows beyond a height of 30 cm. The main stem is coarse and scaly due to persistent bases of old stipules. The roots are somewhat tuberous. The leaves, 30-40 mm in diameter, are roundish to ovate-cordate with crenulate margins. They are apple green and covered with fine short hairs making them pleasant to touch. They have a strong apple-mint scent. The flowers are pale pink and relatively small. 

Plant Type

Distribution

Used for ornamental purposes as well as for its scented leaves, P. odoratissimum has not been reported to grow in the wild outside of its native South Africa, other than as a cultivation escape in Puerto Rico. It is known to be a garden cultivation in the USA, Spain, France, Brazil, Korea, and Puerto Rico (Liogier and Martorell, 2000; Seidemann, 2005). 

Distribution Table

The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.

History of Introduction and Spread

P. odoratissimum is native to South Africa, but most cultivars of this genus that are now grown for their rose-scented essential oil, ‘geranium oil’, came about through breeding experimentation in Europe between introduced species from South Africa and are therefore of hybrid origin (Dasuki, 2002). SANBI (2014) reports that this species was introduced into the UK in 1724 and grown in the Chelsea Garden (London). Commercial cultivation of Pelargonium species began in the early 19th Century in Grasse, France, which remained the European centre of production until World War II (Dasuki, 2002).

Date of this species’ introduction to the West Indies as a cultivated plant is uncertain, but it may have occurred relatively recently, as the species was not included in the principal floras of the region from the nineteenth and early twentieth centuries. Britton and Wilson (1924) did note, however, that many Pelargonium species and cultivars were being grown in Puerto Rico as of 1924. 

Habitat

In its native South African habitat, P. odoratissimum reportedly grows as undergrowth in forests or in shaded places protected by rocky ledges or taller bushes (SANBI, 2014) and under trees in forest margins (PFAF, 2014). In Colombia, the species is cultivated in humid premontane forests (Vascular Plants of Antioquia, 2014). It has been commercially grown on cultivated land, in glasshouses, and in gardens for its oils and an ornamental plant (Hanelt et al., 2001; PFAF, 2014; USDA-ARS, 2014).

Habitat List

Biology and Ecology

Genetics

Sporophytic count = 16 (IPCN Chromosome Reports, 2014).

Reproductive Biology

The species is capable of self-fertilizing and can reproduce both by seed and vegetatively. In South Africa, the species flowers throughout the year except for midsummer (SANBI, 2014).

Environmental Requirements

P. odoratissimum can grow in both dry and moist soils but prefers well-drained, light (sandy) and medium (loamy) soils. It can tolerate a range of pH levels including acid, neutral and basic (alkaline). It can tolerate some shade such as in open woodland, or no shade, but is sensitive to frost (PFAF, 2014).

In Antioquia, Colombia, P. odoratissimum reportedly grows at 1500-2500 m (Vascular Plants of Antioquia, 2014), and in Ecuador it has been reported growing higher, between 2500-3000 m (Vascular Plants of Ecuador, 2014).

Climate

Soil Tolerances

Soil drainage

• free

Soil reaction

• acid
• alkaline
• neutral

Soil texture

• light
• medium

Means of Movement and Dispersal

No data was found on the movement and dispersal of this species in the wild, but it has been reported as an accidental introduction in Puerto Rico, where it has escaped from cultivation (Liogier and Martorell, 2000). P. odoratissimum has been repeatedly introduced intentionally by humans for use in medicine, food preparations, essential oil, and as an ornamental plant. 

Pathway Causes

Pathway Vectors

Impact: Environmental

Little information is available on the potential environmental, economic, health and cultural impacts that this species would have should it become invasive. It is currently not considered a high-risk species, although it is known to sometimes escape from cultivation in Puerto Rico (Liogier and Martorell, 2000). However, considering that many members of this genus are known to be weedy or invasive, P. odoratissimum could potentially become a problem species if left unmonitored.

Risk and Impact Factors

• Tolerates, or benefits from, cultivation, browsing pressure, mutilation, fire etc
• Fast growing
• Has propagules that can remain viable for more than one year
• Reproduces asexually

• Highly likely to be transported internationally deliberately

Uses

P. odoratissimum has been introduced beyond its native range for use as an ornamental flowering plant. The leaves are also used for perfumery and lining pillows (Hanelt et al., 2001; Seidemann, 2005; SANBI, 2014), although there is a debate regarding whether this species produces aromatic oil (see Lis-Balchin, 2002). Plant parts of this species are also used for culinary purposes; leaves can be crushed and used to flavour salads, soups, fruit dishes, jellies, sorbets, ice-cream, cakes, and other baked goods, and an infusion of the leaves is used as a tea (PFAF, 2014).

The leaves of P. odoratissimum have been used as an insect repellent as well as for traditional medicinal purposes. As the whole plant reportedly possesses astringent, tonic and antiseptic effects, it is used internally in the treatment of debility, gastro-enteritis and haemorrhage and externally to treat skin complaints, injuries, neuralgia and throat infections (PFAF, 2014).

Uses List

Human food and beverage

• Food additive

Materials

• Essential oils
• Pesticide

Medicinal, pharmaceutical

• Traditional/folklore

Ornamental

• Potted plant

Prevention and Control

No information was found for methods of prevention and control of this species, as it has not been reported to be usually problematic. Other Pelargonium species that have proved to be weedy sometimes require government assistance to stop infestations using chemicals, such as the case of P. alchemilloides, which is one of 28 plants listed in Australia’s Federal Government Alert List for Environmental Weeds (CRC for Australian Weed Management, 2003).

References

Acevedo-Rodríguez P; Strong MT, 2012. Catalogue of the Seed Plants of the West Indies. Smithsonian Contributions to Botany, 98:1192 pp. Washington DC, USA: Smithsonian Institution. http://botany.si.edu/Antilles/WestIndies/catalog.htm

Britton NL; Wilson P, 1924. Scientific Survey of Porto Rico and the Virgin islands, Volume V, Botany of Porto Rico and the Virgin Islands. New York Academy of Sciences, New York.

CRC for Australian Weed Management, 2003. Garden geranium (Pelargonium alchemilloides) weed management guide. http://www.environment.gov.au/biodiversity/invasive/weeds/publications/guidelines/alert/p-alchemilloides.html

Dasuki UA, 2002. Pelargonium Rosat Group. In: Oyen LPA, Lemmens RHMJ, Eds. PROTA (Plant Resources of Tropical Africa). Wageningen, the Netherlands: PROTA. http://database.prota.org/PROTAhtml/Pelargonium%20Rosat%20Group_En

Hanelt P; Buttner R; Mansfeld R, 2001. Mansfeld's Encyclopedia of Agricultural and Horticultural Crops (except Ornamentals). Berlin, Germany: Springer.

IPCN Chromosome Reports, 2014. Index to Plant Chromosome Numbers (IPCN), Tropicos website. St. Louis, Missouri, USA: Missouri Botanical Garden. http://tropicos.org/Project/IPCN

Liogier HA; Martorell LF, 2000. Flora of Puerto Rico and adjacent islands: a systematic synopsis, 2nd edition revised. San Juan, Puerto Rico: La Editorial, University of Puerto Rico, 382 pp.

Lis-Balchin M, 2002. Geranium and Pelargonium: the genera Geranium and Pelargonium. London, UK: Taylor & Francis, xi + 318 pp.

PFAF, 2014. Plants for a future. http://www.pfaf.org

Randall RP, 2012. A Global Compendium of Weeds. Perth, Australia: Department of Agriculture and Food Western Australia, 1124 pp. http://www.cabi.org/isc/FullTextPDF/2013/20133109119.pdf

SANBI, 2014. South African National Biodiversity Institute plant information website., South Africa: Kirstenbosch National Botanical Garden, South African National Biodiversity Institute. http://pza.sanbi.org/

Seidemann J, 2005. World spice plants: Economic usage, botany, taxonomony. Heidelberg, Germany: Springer, 286-287.

Stearn WT, 1992. Stearns dictionary of plant names for gardeners: A handbok on the origin and meaning of the botanical names of some cultivated plants. London, UK: Cassell.

USDA-ARS, 2014. Germplasm Resources Information Network (GRIN). Online Database. Beltsville, Maryland, USA: National Germplasm Resources Laboratory. https://npgsweb.ars-grin.gov/gringlobal/taxon/taxonomysearch.aspx

Vascular Plants of Antioquia, 2014. Catalogue of the Vascular Plants of the Department of Antioquia (Colombia), Tropicos website. St. Louis, Missouri and Cambridge, Massachusetts, USA: Missouri Botanical Garden and Harvard University Herbaria. http://tropicos.org/Project/CV

Vascular Plants of Ecuador, 2014. Catalogue of the Vascular Plants of Ecuador, Tropicos website. St. Louis, Missouri and Cambridge, Massachusetts, USA: Missouri Botanical Garden and Harvard University Herbaria. http://tropicos.org/Project/CE

Links to Websites

Contributors

2/2/2015 Original text by:

Marianne Jennifer Datiles, Department of Botany-Smithsonian NMNH, Washington DC, USA

Pedro Acevedo-Rodríguez, Department of Botany-Smithsonian NMNH, Washington DC, USA

Distribution Maps