A rather sloppy style of the 1970s combined with a weird color of the 1980s might explain the resemblance of hair grass, Muhlenbergia capillaris, to real hair. The lime otter-pop green color of the foliage, which looks so fresh in the garden, is actually quite dated for hair. So is the pleasantly soft texture. The sparse, fuzzy cloud of purplish pink bloom that hovers just above the foliage in autumn is extraordinary, although only slightly more contemporary for hair color. Happy hair grass plants that get plenty of water in sunny spots can get more than two and a half feet tall. Yet, the perennial foliage is so soft that it tends to fill in space between other sturdier plants instead of overwhelming them.