Blue oat grass is the common name of Helictotrichon sempervirens, an ornamental grass wiely used in landscaping. Native to Central Europe, it is pale green with a tinge of blue. Blue oat grass grows in an arching shrub shape, one and a half to three feet tall. Its Pale blue flowers bloom in May and last through August. The plant is evergreen, or retains its color through the winter. It belongs to Family Poaceae, or true grasses.