Sweet vernal grass is one of the first grasses to bloom early in the season. It is found in both grasslands and ruderal or poor-quality habitats like roadsides.
The following is about the growing requirements, care of, and uses for sweet vernal grass.
General Information
Anthoxanthum odoratum, also known as sweet vernal grass, is a perennial grass with Eurasian roots that was introduced and has now spread across most of North America. It is considered invasive in some regions because it spreads aggressively.
It is an evergreen, cool-season grass that can grow up to almost 2 feet tall. It blooms on grasslands and meadows between April and July. It has thick flower clusters grouped into cylindrical flower spikes supported by stiff stems with broad, flat leaves.
The scientific name for sweet vernal grass means early-blooming fragrant yellow flowers. Green or purple-flushed flower spikelets emerge on the unbranched panicles in late spring or early summer.
It is sometimes referred to as vanilla grass because of the fragrance it releases when cut. The smell is described as a combination of fresh hay and a subtle vanilla scent. The pleasant, fresh hay aroma is caused by the chemical coumarin, also found in sweet woodruff.
Sweet vernal grass was once a popular chewing grass due to its sweet, vanilla-like flavor and aromatic dried state. Brown and skipper butterfly larvae feed on this grass.
Care and Maintenance
Cultivation
Sweet vernal grass thrives in moist acidic soils. It tolerates partial to full shade but grows best in the sun to light shade. It becomes drought tolerant once it is established.
Watering
Irrigation is critical for a plant’s development during the first two years after planting. Keep the soil consistently moist and water as needed. Once mature, weekly watering to root depth should be sufficient.
Pruning
Pruning can be done if cut leaves are required for drying. Otherwise, pruning is unnecessary.
Propagation
Divide in the spring or sow seeds in the fall. You can divide successfully at any time of year; however, it is best to let it self-seed. It usually takes two to three weeks for the seed to germinate.
Landscape Uses
Anthoxanthum odoratum’s fragrance makes it ideal for potpourri or dried flower arrangements. It is known to keep its scent for years. The grass is frequently used on golf course roughs because it grows well in poor soil, and the seeds are inexpensive and abundant.
It is considered invasive in many areas due to its capacity to take over a grassy area rapidly. Sweet vernal is ideally cultivated in containers due to its aggressive spreading tendency. Even when grown in pots, the plant has the potential to spread.
Companion Plants
Allium montanum
This allium cultivar features strong upright foliage, thicker leaves, and vibrant green color. It is an ornamental onion that draws butterflies, bees, and other pollinators to its pink to white flowers.
This plant’s foliage lasts into the fall and can even withstand mild winters in some areas. Also known as German or mountain garlic, it adds diversity to any landscape.
Pycnanthemum muticum
Pycnanthemum muticum, also known as mountain mint, is a fragrant perennial that forms clusters and typically grows 1 to 3 feet tall.
Mountain mint has a strong leaf structure and dark green leaves that smell like spearmint when crushed. When planted in groups or massed, the silvery bracts give the impression that the entire plant is covered in white powdery snow.
Carex caryophyllea
Carex caryophyllea grows in a mound of mop-like leaves. The long leaves of this new cultivar flop to the ground, making it appear reminiscent of The Beatles’ hairstyle.
The soft green leaves have broad, creamy yellow edges. It is a unique sedge that can be planted in containers, rock gardens, or as a low ground cover.
