The leaf:

| Last updated: December 2024 |

This plant is being commercially marketed by nurseries as a mosquito-repelling plant. However, studies conducted several years ago [1, 2] suggest that this claim is unlikely to be true. According to the description in a 1994 article [2], it is "a cross of an African lemon geranium (P. crispum) with an English fingerbowl geranium (P. x limoneum) hybrid that further incorporated tissue cultures of a southern Asiatic grass that produced citronella oil". The botanical name mentioned in the article was Pelargonium x citrosum 'van Leenii' Voigt ex T.

The botanical name Pelargonium citrosum was frequently used for this plant. However, according to the Plants of the World Online website, this name is a synonym of Pelargonium cucullatum subsp. cucullatum. I had written a separate note on this plant back in December 2015.

References:

[1] Matsuda BM, Surgeoner GA, Heal JD, Tucker AO, Maciarello MJ. Essential oil analysis and field evaluation of the citrosa plant "Pelargonium citrosum" as a repellent against populations of Aedes mosquitos. J American Mosquito Control Association 1996;12(1):69-74. | Abstract |

[2] Cilek JE, Schreiber ET. Failure of the "mosquito plant", Pelargonium x citrosum 'van Leenii', to repel adult Aedes albopictus and Culex quinquefasciatus in Florida. J American Mosquito Control Association 1994;10(4):473-476. | Abstract |