appearance black 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 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 angles building capping cleaning cover covered covering danger dangers ear protection edge exterior external height high high-pressure improvement maintenance pressure pressure-cleaning renovating renovation repairs restoration restoring risks risky roof roof-area roofing rooftop safety skies sky spray sunlight sunshine tiles tiling tools water wet work workman