engelmanns prickly pear cactus in organ pipe national monument in the sonoran desert of southwest arizona

agave ajo america arid arizona bloming bloom blooming blossom buds cactaceae cacti cactus clouds colorful desert drive dry engelmanns flora flower green hot landscape monument mountain mountains national natural nature organ park pear pipe plant plants prickly red rocks saguaro sky sonoran southwest southwestern spring trail travel usa valley vegetation west wilderness