''Pelargonium'' 'citrosum' (often sold by the invalid

binomial name In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

''Pelargonium citrosum'' ) is a perennial

subshrub A subshrub ( Latin ''suffrutex'') or dwarf shrub is a short shrub, and is a woody plant. Prostrate shrub is a related term. "Subshrub" is often used interchangeably with "bush".Jackson, Benjamin, Daydon; A Glossary of Botanic Terms with their ...

with fragrant leaves that are reminiscent of citronella. PelargoniumCitrosum

''P.'' 'citrosum' is marketed as "mosquito plant" or "citrosa geranium" in stores in the United States and Canada, even though research from the University of Guelph indicates the plant is ineffective against ''

Aedes aegypti ''Aedes aegypti'', the yellow fever mosquito, is a mosquito that can spread dengue fever, chikungunya, Zika fever, Mayaro and yellow fever viruses, and other disease agents. The mosquito can be recognized by black and white markings on its l ...

'' mosquitos. "Not only was the plant ineffective at protecting humans against Aedes mosquito bites, the mosquitoes were seen landing and resting on the citrosa plant on a regular basis." It is claimed that ''P.'' 'citrosum' may be a genetic bonding of the African geranium with genes from

Cymbopogon ''Cymbopogon'', also known as lemongrass, barbed wire grass, silky heads, Cochin grass, Malabar grass, oily heads, citronella grass or fever grass, is a genus of Asian, African, Australian, and tropical island plants in the grass family. Some ...

grass, but that claim has also been proven false. The plant appears to be a cultivar of ''

Pelargonium graveolens ''Pelargonium graveolens'' is a ''Pelargonium'' species native to the Cape Provinces and the Northern Provinces of South Africa, Zimbabwe and Mozambique. Etymology ''Pelargonium'' comes from the Greek πελαργός ''pelargos'' which means st ...

''. The citronella geranium is not to be confused with others that are also called " mosquito plant", nor with the group of plants also known as citronella grass, or with ''

Citronella mucronata ''Citronella mucronata'', the huillipatagua () or Chilean citronella tree, is an evergreen tree native to Chile, it occurs from 30 to 41° South latitude. In Chile, the tree grows from 500 to 2000 meters above sea-level in low altitude interio ...

'' (Chilean Citronella). ''Pelargonium'' 'citrosum' is hardy to USDA Zone 10–11.

References

External links

''Is This Plant a Hoax?''
by Arthur O. Tucker and Michael J. Maciarello, Department of Agriculture & Natural Resources, Delaware State College
IPNI Listing

Kew Plant List
citrosum Ornamental plant cultivars {{Geraniaceae-stub