abstract algae background bacteria bacterium bog canal environment environmental fen goo gooey green grunge grungy lake marsh mat nature plant poison poisonous pond scum Slime slimy stagnant swamp texture thick toxic water weed wet 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 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