Anthoxanthum odoratum, also known as sweet vernal grass, holy grass, vanilla grass, or buffalo grass, is a flowering plant in the grass family Poaceae. It is a short-lived perennial plant native to acidic grassland in Eurasia. It is grown as a lawn grass and a house plant, due to its sweet scent, and can also be found on unimproved pastures and meadows. 'Odoratum' is Latin for 'odorous'.
Anthoxanthum odaoratum grass grows in tufts with stems 25-40 cm (9.8-15.7 in) tall, and short, broad green leaves 3-5 mm (0.12-0.20 in) wide, which are slightly hairy. It flowers from April until June, i.e. quite early in the season, with flower spikes of 4-6 centimetres (1.6-2.4 in) long and crowded spikelets of 6-10 mm (0.24-0.39 in), oblong shaped, which can be quite dark when young. The lower lemmas have projecting awns.
The ligules are quite long, up to 5 mm (0.20 in), blunt, with hairy fringes around the side.
The scent is particularly strong when dried, and is due to coumarin, a glycoside, and benzoic acid - it smells like fresh hay with a hint of vanilla. The seed head is bright yellow in color. It avoids very dry or waterlogged soil.
It is grown by scattering seed on tilled ground in the spring through fall, germinating in 4 to 5 days. It prefers sandy loam and acidic conditions (a low pH).
As an agricultural grass it has a low yield, but can grow on land too acidic for other grasses.