Anthoxanthum odoratum
sweet vernal grass
Europe, North Africa, and temperate Asia
Overview
Anthoxanthum odoratum is a tufted, cool-season perennial grass growing 8-24 inches (20-60 cm) tall in dense clumps. The flat, soft leaf blades are 2-6 inches (5-15 cm) long and bright green, and the whole plant carries the scent of coumarin, producing the smell of fresh hay when cut or dried. Narrow, spike-like flower panicles 1-3 inches (2.5-7.5 cm) long appear from April to June, green at first and turning straw-brown as the small spikelets shed pollen and ripen seed. It is among the earliest grasses to flower in spring. Native to Europe, North Africa, and temperate Asia, A. odoratum grows in meadows, pastures, heaths, and open woodland on a range of soils, and has naturalized widely across North America and other temperate regions. It tolerates poor, acidic ground and some shade but is short-lived and seeds itself freely, which can let it spread into lawns and managed grassland. The coumarin content makes the foliage bitter to grazing stock. Plants die back in cold winters and regrow from the base in early spring. It is hardy to USDA zone 4.
Native Range
Native to Europe, North Africa, and temperate Asia. Introduced to North America, Australia, and other regions, where it has naturalized in meadows, pastures, roadsides, and lawns.Suggested Uses
Grown in wildflower meadows, naturalized lawns, and scented and sensory plantings. Sown at roughly 6-12 inches (15-30 cm) spacing or broadcast in a meadow mix, it adds early flowering and a hay fragrance among other grasses and forbs.How to Identify
Appearance
Size & Dimensions
Height8" - 2'
Width/Spread6" - 1'
Reaches mature size in approximately 2 years
Bloom Information
Flower panicles emerge from April to June, earlier than most meadow grasses. The green spikes turn straw-brown as they shed pollen and ripen. Wind carries the pollen, which is a recognized contributor to early hay fever.
Detailed Descriptions
Flower Description
Green to straw-brownFoliage Description
GreenGrowing Conditions
Sun Requirements
Requires 4-9 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Care & Maintenance
Care Guide
Anthoxanthum odoratum grows in full sun to partial shade in moist to dry soil across a wide pH of 4.5 to 7.0, and tolerates poor, acidic, and low-nutrient ground. It needs little water once established and withstands drought by going semi-dormant. The grass is hardy to USDA zone 4 and regrows from the base each spring. Because it self-seeds readily, mowing or removing seed heads before they ripen limits unwanted spread. It has no significant pests or diseases. No fertilizer is needed, and rich soil favors coarser grasses that crowd it out.Pruning
Cut or mow the clump to a few inches in late winter to clear old growth before the spring flush. Removing the seed heads after flowering reduces self-sowing. The dried foliage retains its scent and is sometimes cut for use in sachets.Pruning Schedule
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winter