abstract art background decoration design floral flourish flower graphics leaf ornament plant square texture wallpaper alien Fallopia japonica foreign invader invasive Japanese Knotweed natural nature nuisance pest weed circle cluster group head pattern Sardinia symmetrical symmetry umbel umbellifer white cardoon cynara cardunculus edible England english garden Great Britain purple stamens vegetable Greece Greek green hills hillside landscape mountains path plants rough spring stony track trail golden herb leaves oregano Origanum vulgare yellow Apulia bindweed Convolvulaceae convolvulus flowers fresh Gargano italian Italy New pink Puglia christmas cone conifer evergreen norway Picea abies scale seed softwood spruce tree