Structure of Nut Grass

Nut grass is difficult to remove.

Nut grass, a troublesome lawn and garden weed in the United States and elsewhere, grows upright from a complex system of roots, rhizomes, bulbs and tubers that make it difficult to remove or treat with herbicides.

Fundamentals

Nut grass, also known as nut sedge, develops a strong, expansive root system out of which leaves grow in groups of three. Young nut grass plants form thick white rhizomes--essentially shallow, horizontal subsurface stems. As the rhizomes mature, they form a bulbtype growth that sprouts tuber roots which then produce new rhizomes to continue the plant's spread. This dense growth in all directions makes nut grass one of the most difficult weeds to remove from lawns and gardens, according to Agro Lawn Systems.

Nut grass reproduces mainly by expansion through its network of rhizomes and tubers, but also develops as many as 1,500 seeds per plant that, if dispersed into wet soil, produce new plants.

The plant's name comes from the nut-shaped tubers. While it looks like a grass plant and grows among other grasses, it is not a true grass.

Characteristics

Nut grass has wide yellow-green leaves that are smooth or waxy on the upper side, according to Agro Lawn Systems. It can grow up to 3 feet in height if not mowed.

Nut grass tolerates all soil types, ranging from sandy to hard-packed clay, but is most invasive in wet, sunny areas, according to the Ohio Perennial and Biennial Weed Guide. It does not grow in shade.

Habitat

Nut grass originated in warm, wet regions of Europe, Asia and North America but has spread to temperate areas, according to the Ohio Weed Guide. Before 1950, it grew mostly in native habitat along riverbanks and in marshes, but it has since moved aggressively into cultivated fields, lawns and gardens, particularly in the north-central and northeastern areas of the United States.

It has been found in all 50 states and through much of the world's warm and temperate areas, according to the Washington State Noxious Weed Control Board.

Growth

Nut grass seeds germinate in May and the resulting plant flowers through the summer, producing more seeds to germinate the following spring, according to the Ohio Weed Guide. Tubers grow once soil temperatures reach about 54 degrees F, and shoots grow from those tubers through mid-July. New tubers are formed in late July and continue until hard frost.

Only the tubers and seeds survive the winter to produce new growth in the spring. The leaves, rhizomes and bulbs die with the first hard frost, according to the Ohio Weed Guide. Tubers live for about 3 or 4 years.

Benefits

Nut grass tubers have a mild starchy taste that is popular with pigs, according to the Ohio Weed Guide. Ancient Egyptians cultivated the tuber as a food, and it is still grown in southern Spain for use in a nonalcoholic beverage.

Farmers in the southeastern United States grow an African variety of nut grass called chufa for its edible tubers.

Control

Nut grass is resistant to many herbicides and spreads rapidly as other weeds die, according to the Washington State Noxious Weed Control Board. Its complex root system makes it difficult to pull or dig out of the soil. Damaged or broken tubers will continue to produce new shoots.

References

• Agro Lawn Systems: About Nut Grass
• Ohio Perennial and Biennial Weed Guide: Nut Grass
• Washington State Noxious Weed Control Board: About Nut Grass

Resources

• How to Get Rid of Stuff: Controlling Nut Grass