brightly-coloured brown carpeting-plants clump-forming clumps color coloration colored colorful colors colour coloured colourful colours common contrast contrasting daisy-like drought-tolerant environmental-weed flower flowers garden-flowers gazania gazanias golden hardy introduced-species invasive low-growing perennial plants prolific rapid-spreader resilient roadside-weeds South-African streaked tough vivid water-wise weed widespread wind-blown-seeds winter yellow