Knotgrass (Distichum)

The Knotgrass (Distichum) is generally described as a perennial graminoid. This is native to the U.S. (United States) has its most active growth period in the spring and summer and fall . The greatest bloom is usually observed in the late summer, with fruit and seed production starting in the summer and continuing until fall. Leaves are not retained year to year. The Knotgrass (Distichum) has a short life span relative to most other plant species and a rapid growth rate.

The Knotgrass (Distichum) is easily found in nurseries, garden stores and other plant dealers and distributors. It can be propagated by seed, sprigs. It has a moderate ability to spread through seed production and the seedlings have high vigor. Note that cold stratification is not required for seed germination and the plant cannot survive exposure to temperatures below -13°F. has none tolerance to drought and restricted water conditions.

Uses of : Landscaping, Medicinal, Culinary, etc.

Livestock: Knotgrass is valuable forage in areas of high salinity. It is recommended that knotgrass is lightly grazed and given a rest period of approximately 2 ½ to 3 months because the rooted stolons are often floating. It can be made into hay but is not suitable for silage.

Ornamental Landscaping: Knotgrass is used in golf course turfs and lawns.

Wildlife: It is grazed by many mammals and is considered a substantial source of food for ducks in Louisiana marshes.

Erosion: Knotgrass is recommended in the restorations of wetlands, marshes, beaches, and stream banks.

Conservation Practices: Knotgrass, because of its growth habit, potentially has application when established with certain conservation practices; however, conservation practice standards vary by state. For localized information, consult your local NRCS Field Office. NRCS practices include the following: 327-Conservation Cover; 342-Critical Area Planting; 386-Field Border; 390-Riparian Herbaceous Cover; 393-Filter Strip; 512-Pasture and Hay Planting; 550-Range Planting; 560-Access Road; 562-Recreation Area Improvement; 643-Restoration and Management of Declining Habitats; 644-Wetland Wildlife Habitat Management; 647-Early Successional Habitat Development/Management; 656-Constructed Wetland; 657-Wetland Restoration; 658-Wetland Creation; 659-Wetland Enhancement.

General Characteristics

General: Grass Family (Poaceae). It is a perennial which may be creeping or growing in clumps. The creeping stems produce roots at the nodes in which flowering stems emerge. The culms are firm and range in heights up to 1½ feet. The nodes on creeping stems are often pubescent whereas the nodes on the mat-forming stems are glabrous. The sheaths are loose and glabrous to pubescent. The blades are flat and taper to an inrolled apex. They are 2 to 6 inches long and about 1 inch wide. The flowering stem bears terminal digital racemes in 2’s or 3’s, that are up to 3 inches long. Axes are winged and glabrous with thin, dry margins. The spikelets are solitary and straw-purple in color. The first glume is rarely present. The second glume and sterile lemma are glabrous and 3-nerved. The grain is yellowish and oblong to ellipsoid.

Required Growing Conditions

Knotgrass is found in both wet and well-drained areas. It frequents meadows, marshes, and ditches. It can also be found in cultivated or disturbed areas, and bordering wooded areas. It is located throughout the southeast United States, Arkansas, Texas, Oklahoma, and in the western United States. It is native to Louisiana. For current distribution, consult the Plant Profile page for this species on the PLANTS Web site.

Cultivation and Care

Adaptation: Knotgrass can tolerate high salinity and a waterlogged environment. It has no tolerance of shade. New growth starts in early March and it stays green until the first frost.

Knotgrass reproduces from rhizomes, stolons, and seeds. It can be easily established by sowing stolons in damp holes. If planted in water, knotgrass will remain green throughout the year.

Knotgrass may flower throughout the year. The seeds may be gathered; however, they require a period of dormancy. The seeds yield their highest germination when temperatures are between 82 to 95º F and when they receive about 16 hours of light. Ripening can be sped up with dry storage at 122º F. Also, scarring the seeds with acid may increase germination.

It is not recommended to mix knotgrass seeds with cool season grass seeds. In parts of the United States where cool season grasses dominate, the warm season grasses can be taken over because they develop slower than the cool season grasses. It is also recommended that seed not be moved more than 300 miles north, 100 miles east or west, or 200 miles south of its point of origin.

General Upkeep and Control

Tilling knotgrass on a dry surface will increase stolons to root and encourage a denser sod. Grazing also increases knotgrass. It withstands burning if water is above soil surface. The rhizomes enable knotgrass to survive fire. It sometimes can be troublesome by blocking irrigation ditches. In direct-seeded rice it is a serious weed that grows vigorously under favorable conditions. Check with the local extension service for recommended herbicides. Knotgrass has no known pests or problems. PAHE2"Sometimes, maidencane can become a weed in moist cultivated fields. If it becomes a weed, then periodic mowing is recommended. Spraying herbicides in dense stands can create openings. Check with the local extension service for recommended herbicides. Maidencane has no known pests or problems. "

Plant Basics
Growth Rate Rapid
General Type Graminoid
Growth Period Spring, Summer, Fall
Growth Duration Perennial
Lifespan Short
Plant Nativity Native to U.S.
Commercial Availability Routinely Available
Physical Characteristics
Bloom Period Late Summer
Displays Fall Colors No
Shape/Growth Form Stoloniferous
Drought Tolerance None
Shade Tolerance Intolerant
Height When Mature 0.9
Vegetative Spread Moderate
Flower Color Green
Flower Conspicuousness No
Fruit/Seed Abundance Low
Fruit/Seed Seasonality Summer Fall
Seed Spread Rate Moderate
Gardening Characteristics
Propagations (Ways to Grow) Seed, Sprigs
Moisture Requirements High
Cold Stratification Required No
Minimum Temperature -13
Soil Depth for Roots 4
Toxic to Nearby Plants No
Toxic to Livestock No
After-Harvest Regrowth Rate Moderate
After-Harvest Resprout Ability No
Responds to Coppicing No
Growth Requirements
pH Range 4.9–8 pH
Precipitation Range 30–30 inches/yr
Planting Density 10912–43560 indiv./acre
Soil Textures Fine, Medium
Soil Depth for Roots 4
Minimum Frost-Free Days 220 day(s)
Salinity Tolerance High
CaCO3 Tolerance High
Sustainability & Use
Leaf Retention No
Palatability High
Fire Resistant No
Causes Livestock Bloating None

Source: USDA, NRCS, PLANTS Database,
National Plant Data Center, Baton Rouge, LA 70874-4490 USA