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