Populations of P. spicata from warm, arid environments are often smaller with earlier phenology, narrower leaves, and have greater leaf pubescence.

[5] The stems and leaf sheaths of P. spicata dominate photosynthetic carbon uptake during the late spring and summer seasons.

Additionally, bluebunch wheatgrass shows a greater investment of biomass and nutrients in the stems and sheaths, causing an increase in photosynthetic capacity per unit surface area.

[9] Pseudoroegneria spicata can be found in the United States, Canada, and Mexico from Alaska and Yukon south as far as Sonora and Nuevo León.

[4][10][11] It is the dominant species of grass among the mountainous regions of the western United States, occurring at elevations that range from 150–3,000 m (490–9,840 ft) and where precipitation is 250–500 millimetres (10–19+1⁄2 in).

Such behavior suggests that the roots of bluebunch wheatgrass are capable of detection and avoidance mechanisms when exposed to intraspecific plants from the same population.

[12] Pseudoregneria spicata is outcompeted by noxious weeds such as diffuse knapweed (Centaurea diffusa) and medusahead (Taeniatherum caput-medusae).