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Organic Control of Johnson Grass

By Bobbie Brewer ; Updated September 21, 2017
Pulling weeds is jsut one way to rid lawn and garden of johnsongrass invasion.

Johnsongrass is a problematic weed for gardeners. If Johnsongrass spreads uncontrolled, it can quickly take over gardens, lawns and pastures. This resilient weed with its tough root system is difficult to eliminate once it is established. There are, however, organic methods that can help slow the progress of this annoying weed in your landscape.


Johnsongrass (Sorghum halepense) is a tough, fibrous grass that grows in large clumps. Seedlings can be spotted by their resemblance to corn plant seedlings, and the weed has an oval seed that is black or brown. The flat-bladed stems of Johnsongrass are rigid and easily snap. They are light green to reddish-colored when mature and can grow 6 to 7 feet tall. The plant produces green to purple-brown flowers from the month of May to October.


Johnsongrass is tough to destroy and spreads easily because of its rhizome-like root system that stems outward and sprouts under the ground. The stems are thick and grow in segments capable of sprouting roots and a new plant. One Johnsongrass plant is capable of producing several new plants. When ridding a garden or pasture of Johnsongrass, the fleshy segments of the underground stems must be destroyed.


Preventing the weed from firmly establishing itself is the best method of organic control. Identify and pull Johnsongrass seedlings. Since it can sprout readily from seed, others will likely be growing nearby. Removing seedlings in the spring before they can grow to maturity will prevent the underground plant stems from segmenting into new plants.


Mowing is an organic alternative to spraying for Johnsongrass when dealing with lawns and grass crops. Mow grass regularly to prevent stands of Johnsongrass establishing itself in your lawn. This can keep the numbers of weed plants low and make them easier to manage. An alternative to using a lawnmower is to allow livestock to graze. For fallow fields and pastures, grazing cattle can control Johnsongrass throughout the summer. Weeder geese effectively control Johnsongrass in smaller plots.


Smothering the problematic weed is an alternativ to using herbicidal sprays that might prove to be harmful to crops and animals. Smothering involves rotating crops that grow densely enough to choke out emerging Johnsongrass seedlings. Winter-annual grain grasses, legumes, and alfalfa can work well as long as the weeds are not too prevalent at the time crop rotation begins.


About the Author


Bobbie Brewer has been writing since 1990, with work appearing in print and online. She covers topics related to international travel, outdoor recreation, parenting and gardening. Brewer holds a Bachelor of Arts in English from California State University, Sacramento.