Common bugloss, Anchusa officinalis, Boraginaceae (Borage). The photos below are all from the same plant seen on the Lion’s lair trail 06162017, in Boulder. This is the only plant I noticed and the first time I have seen this.
It is on the CO dept. of Agriculture noxious weed watch list. Watch List Species are potential threat to environment or agriculture. Citizens are encouraged to report these species. Out of curiosity, I opened the online form and found it was easy to submit this sighting. I received an immediate e-mail reply: “Thank You! We received your Invasive Plant Spotter Form! We will contact you if we need any additional information.”
Boulder wildflowers 