Johnson grass – Sorghum halepense

Sorghum halepense

Sorghum halepense

The Johnson grass (Sorghum halepense) is one of the most damaging pest plants for many crops. It will mainly affect the corn crops, sunflower and soy plants, but it will also have negative effects on other crops, such as: the flax, peas, sorghum, chickpeas, beans, sugar beet, etc.

Common names: Johnson grass or Johnsongrass, Sorghum halepense.


The Johnson grass is a thermophilic and a sun-loving species that best grows on irrigated parcels, or on parcels that have access to groundwater.

It has a well-developed root system, due to which it can withstand to drought. The Johnson grass is a perennial plant that produces stolons. The plant’s underground parts are: rhizomes and side roots. Most of these parts grow in different directions, but most of them vertically extend into the soil, and this is what offers the plant its resilience to drought.

The rhizomes are underground stems that are formed of knot and inter-knots that the Johnson grass uses for the vegetative multiplication. Every knot has buds that will form new plants. The thickness of the rhizomes ranges from 1 to 10-cm and the diameter from 1-3-cm.

Sorghum halepense - roots

The stems of the Johnson grass plants are simple, vertical, smooth, and its height is 1-1.5-m.

Sorghum halepense - stem

The leaves are straight and lanceolate, flat, 1-2-cm wide, with long and sharp ends, with no hairs, and with a strong and white middle vein. The panicle is pyramidal and branched, 20-25-cm long, with long and erect branches. The spikelets are 5-mm long, grouped 2-3 and their base is covered in hairs.

Sorghum halepense - leaves

The spikelet: the sessile one, is hermaphrodite, oval and elongated and the male one is 5-mm long and pedicellate, 1.5-2-mm wide, with oval-elongated gums, yellow or brown and covered by smooth and glued hairs.

Sorghum halepense - spike

When they reach maturity, the fruits are shaken off. A Johnson grass plant can grow between 2000 to 6000 seeds, so that within one square meter you can find between 1500 to 5000 shaken seeds.

The seeds’ germination period is during and spring and summer seasons and the blossoming period is during the summer and autumn seasons.

How to fight this pest plant

The herbicides we recommend to fight the Johnson grass are: Accent 75 WG, Equip, Principal, Titus Plus, Gat Motion.

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