Lappula squarrosa is a species of flowering plant in the borage family known by several common names, including European stickseed, bur forget-me-not, bluebur, and bristly sheepbur. It is native to Europe and Asia, where it is common, and it is an introduced species in much of North America and Africa. It is well known as a noxious weed where it is naturalized and also in many parts of its native range.
https://inaturalist.ca/observations?project_id=69401&taxon_id=77626&place_id=any&verifiable=any
When are they blooming in Banff National Park? Late June at the earliest. Full bloom usually between mid-July and early August. Bloom/seeding continuing on until mid September.