A common plant which may be poison hemlock.
Typically blooms in June-July here (wildflower.org says as late as mid-September), but this is apparently remontant
Achillea millefolium, known commonly as yarrow /ˈjæroʊ/ or common yarrow, is a flowering plant in the family Asteraceae. It is native to temperate regions of the Northern Hemisphere in Asia, Europe, and North America. In New Mexico and southern Colorado, it is called plumajillo (Spanish for 'little feather') from its leaf shape and texture. In antiquity, yarrow was known as herbal militaris, for its use in stanching the flow of blood from wounds. Other common names...