Linum lewisii Pursh
Perhaps the best known and toughest of the western wildflowers, this is the lovely blue flower seeded along roadsides. It is extremely prolific and drought tolerant. Flax blooms primarily in the early summer and then sheds seeds for the rest of the growing season. Sufficient moisture will prolong flowering or even restart flowering late in the summer. It can become a garden pest but can be a great addition to less-cultivated areas, such as open spaces and roadsides. Cutting back plants by about half after flowering can help control reseeding.
Water needs: low
Exposure: full sun
Availability in nurseries: common (you can also ask around to see if a friend has some) and easy to start from seed
Native range: western and northern North America (WY native)
Plant family: Linaceae
Photo by Jennifer Thompson