Solidago altissima

Very common tall goldenrod of old fields and similar open spaces. Quite aggressive, to the point of being a native "invasive" in meadows and gardens. Solidago altissima is found throughout much of North America, but there are two subspecies. In the East, and probably introduced to the Western US, is S. altissima ssp. altissima. Native to the Central US is S. altissima ssp. gilvocanescens. See Botphoto.info for identification clues.