Coleus caninus, synonym Plectranthus caninus, also called dogbane, piss-off plant[
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Description
It is a perennial herb covered in small hairs that features narrow, obovate leaves that are approximately 3–4 cm long and 2–4 cm wide, with semi-erect branches. The pale blue-purple flowers have a succulent and tubular appearance, where the then open on the tall inflorescence spike.
Both the leaves and flowers of the plant are sticky to the touch and have an odor similar to Eucalyptus that some animals find unpleasant, deterring both insect infection and grazing by larger animals.
Distribution
It is native to southern Africa and eastern Africa and South Asia: Angola, Botswana, Burundi, DR Congo, Eritrea, Ethiopia, India, Kenya, Myanmar, Namibia, Northern Provinces, Rwanda, Somalia, Sudan-South Sudan, Tanzania, Uganda, Zambia, Zimbabwe.[
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Cultivation
The plant is supposed to scare off cats and dogs who may smell the aroma on the intact leaves and be repelled, hence its common name. Though there is no scientific evidence to show that these claims are factual. An attempt to register " Coleus canina" to receive plant variety protection failed as it was considered to be only a clone of Coleus comosus (synonym Plectranthus ornatus).[
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These plants root easily from cuttings, tolerating mild drought conditions and full sun to part shade. Too much shade causes the stems to become leggy, as they stretch up to look for the sunlight, while the foliage lags behind. It does not tolerate frost and it prefers moist soils, though when established it can tolerate drier conditions.[
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Subspecies
Two subspecies have been described:[
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Coleus caninus subsp. caninus – northern Tanzania to Eritrea, India to Myanmar
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Coleus caninus subsp. flavovirens (Gürke) A.J.Paton, synonyms Coleus flavovirens, Plectranthus caninus subsp. flavovirens – South Africa to Ethiopia
