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