Wet summer brings on coleus-like weed
The heavy rains this season have resulted in a greater-than-usual outbreak of an alien weed that is part of the mint family , and related to the colourfullyleaved coleus plants one often has in one ' s garden and home . It is Plectranthus comosus , commonly known
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during autumn and winter Harlequin ladybirds typically gather in large numbers around urban developments . When disturbed , adults exude a fluid with an unpleasant smell that can also stain fabrics . If you encounter a site with high abundance of Harlequin ladybirds ( eg, more than 20 beetles ) or a large aggregation such as those typically found as Abyssinian coleus , or woolly plectranthus . There are about 350 members of the Mint family ( Lamiaceae ), occurring worldwide ranging throughout Africa , India , Australia and even Japan . Of the 53 species in South Africa and Namibia it is those
around households in window frames and doors , you can contribute to the project by collecting ten to 30 ladybirds per site . All that is needed is that you place these ladybirds in a small , clean container or ziplock bag , note the date and site of collection , and freeze them in your home freezer . Once you have collected them , you can email researcher Dr Minette Karsten at minettek @ sun . ac . za and from the Eastern Cape and KZN that are most suitable as garden subjects . Plectranthus is not only very easy to grow , the plants also tolerate a wide range of conditions , from full shade through to full sun and from damp to dry . Unfortunately Plectranthus comosus , from North Africa -
LADYBIRD
she will contact you with information on how to send your sample . The specimens that you collect will be highly valuable to answer key questions of the invasion biology and will be used in a genetic study to uncover the origins , route of invasion and spread of the Harlequin ladybird in South Africa .
* Traditional English nursery
ALIENS
hence its common name Abyssinian coleus - has become a problem in some areas of South Africa , and is particularly evident this year in Gauteng . Woolly Plectranthus is a Category 3 weed . It grows without any effort , is hardy and can make an eyecatching display when in flower , all of which contributes to making it a lowmaintenance favourite with gardeners . To its discredit is the fact that it readily outcompetes indigenous plants and is therefore detrimental to natural vegetation . Woolly plectranthus is a robust erect shrub up to 3m tall with a woody base . The stems and leaves are densely woolly . Leaves are large , sometimes more than 100mm
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