Blue Oat Grass

Blue oat grass forms a rounded, bristly clump of narrow steel-blue blades, bringing cool color and fine texture to sunny gardens. It usually reaches about 18–24 inches tall and nearly as wide, with taller oat-like flower stems appearing where flowering is reliable. ## Planting and landscape use Give it full sun or very light shade and sharply drained soil. It can tolerate heavy clay when water does not linger around the crown through winter. Use a clump as an accent in a rock garden or container, or repeat plants along a walk, in a border, or at the front of a shrub planting. Its blue blades contrast well with green or deep maroon foliage. ## Seasonal interest The cool-season foliage is steel blue through active growth and often turns light brown in autumn. Leaves may persist through winter, although they die back in colder regions. Flower panicles rise well above the mound but can be sparse in the Upper Midwest. [University of Wisconsin–Madison Extension](https://hort.extension.wisc.edu/articles/blue-oat-grass-helictotrichon-sempevirens/) describes its size, winter behavior and site needs. ## Maintenance Rake away old foliage in late winter or early spring. Keep the crown well drained, especially in winter, to reduce the risk of crown rot.