blue sky clouds color colorful flower grass green hills landscape meadow mountains summer sun tree trees white wildflower yellow blue bushes foam nature reed river rivulet sky spring stream water waterfall waves cold Coniferous Tree december drop February freezing rain frost frozen hanging ice icicle January march needle pine tree snow Spruce Tree transparent weather winter background leaf leaves palm saavem texture cypress thuja twigs wallpaper green hill hill rural bridge forest lake park pond wooden reflections swan beach holiday holidays island palms plant plants sunny sunshine tropical vacation biology botany photosynthesis veins venation