Perennial ryegrass was originally planted as a turf grass in lawns, but its spread is becoming problematic. It is found in agricultural land, wetlands, and disturbed soil areas. In Australia and New Zealand, it is viewed as invasive environmental weed, and it is included on the state invasive species list in both California and Alaska. It can be toxic to both humans and grazing animals. These grasses generate large amounts of seed which are easily spread. The grass outcompetes local plants and leads to a reduction in wildflowers. In a garden setting, perennial ryegrass can be controlled by hand pulling or digging, but otherwise herbicides are needed for larger areas.

Once the weeds start to flower and fructify, it will be difficult to control them effectively. In fact, the best time to remove weeds is before flowering and fructification because the seeds will spread rapidly after that. So, it is necessary to remove weeds more often and to take precautions in advance next year. Mulching: During the seed stage, covering with sawdust, straws or black mulches to effectively inhibit seed germination and the growth of the seedling. Generally, this method is used in winter or spring to inhibit the germination of weed in the soil. If the weeds have already flowered and fructified, this method can be used to isolate the seeds and the soil to prevent the seeds from falling into the soil. Pulling out: Before the weeds fructify, wear gloves or use tools to pull them out. If it is difficult to pull out weed due to dry soil, adding water to the soil helps to make it easy to remove the roots thoroughly. After pulling out the weed, deep tillage can be adopted to remove the residual roots. This method is especially effective for weeds that are in the seedling stage or low growing size. Pruning: Pruning weeds before they fructify can effectively control the propagation of weeds. It is suggested to prune this weed repeatedly, twice a week straight for two weeks during the growth phase. Plowing: Before cultivation, plow the soil, collect and discard the roots of perennial weeds, then expose them to the sun or bury them deeply. It can also be used for retting organic fertilizer and composting. Chemical control: Using appropriate herbicides can effectively remove the weed from the area. Note: When removing weeds, it is necessary to wear gloves to avoid direct contact with the weeds, especially for the ones that are poisonous, thorny and allergenic. When removing weeds at the flowering stage, special masks should be worn to prevent allergic reactions caused by the inhalation of pollen.