Cotoneaster sp. The Cotoneaster sp has its origins in the northern hemisphere. Two that have become invasive in our country came from China. Our su bjects areCotoneaster franchetti (commonly known as orange cotoneaster) and C. pannosus (silver-leaf cotoneaster)(illustrated). The species belong to the Rosacea family. These plants are a familiar sight in almost every garden in our area and obviously they thrive here – our cooler and milder climate being a significant contributing factor. The plants have small flowers that are definitely not the reason for their popularity. Those arching sprays of brilliantly hued berries are simply stunning. Something for parents and grandparents with young children to bear in mind – those fruits with all the appeal, ingested in quantity are in fact poisonous. Clearly the berries are just as popular with our feathered friends (birds can eat many things we can’t) and herein lies some of the rub. Another interesting little red flag I came across was that during the eighties, the species’ potential for natural hybridization led to confusion among growers as to the true identities of some species, and C.X cornubius is listed as of “Garden” origin. Add to that the ease of seed germination and propagation from cuttings and layering and the recipe for invasion is to hand.
Identification: Keen gardeners will already be familiar with these – so this is for the uninitiated. The plants grow into substantial shrubs with long gracefully arching branches without thorns. Generally the young branchlets and undersides of the leaves are densely “felty”. In time the grey-green foliage of Cotoneaster franchetti (commonly known as orange cotoneaster) becomes glabrous (without hairs) and shiny above, while the berries are orange-red in colour. C pannosus (silver-leaf cotoneaster) has dull-green foliage and its fruits are a dull deep red colour.
Invasive Status: The ease of propagation from seed and late summer cuttings underlie the Cotoneaster’s invasive status. To all intents and purpose they also appear to be disease and pest resistant. They are quick growers and invade forest margins, kloofs and riverbanks and also grassland. We have identified and removed adult specimens along Hillside road and seedlings in our own backyard. Cotoneaster species are potential transformers and are classified as declared Category 3 invaders (no trade or new plantings permitted).
Control: There is no herbicide registered for the control of Cotoneaster sp. Therefore use manual control, (hand-pull) for any seedlings and physically remove the entire plant in the case of mature specimens, whenever and wherever you come across escapees from home gardens.
Indigenous substitutes: Salvia africana-lutea (Beach salvia),Salvia africana-caerulea (Bloublomsalie), Salvia chamelaeaganea (Salie)(blue & white forms), Athanasia parviflora (Coulter bush), Tecoma capensis (4 colour forms), Leonotis leonorus (three colour forms)