Sorghum sudanense Seeds | Sudan Grass
LATIN NAME: Sorghum sudanense
COMMON NAME: Sudan Grass
Plant Profile
Unlike the solid, pithy canes of grain sorghum, Sudan grass keeps a thin-walled, hollow stem that stays flexible until late in the season. The open, feathery panicle sheds wind better than a tight head, and the small spikelets are mostly self-pollinated but will cross on a breezy day. Chromosome number is 2n = 20, identical to cultivated sorghum.
Grain sorghum is bred to fill a heavy head and then stop; Sudan grass is bred to keep leafy, to tiller from the base, and to throw a new flush of stems after cutting. The leaf-to-stem ratio stays high well into growth, which is the whole point for a fodder crop. Seed of the species first reached the United States around 1909, sent from the Sudan and giving the grass its common name.
For dairy and beef cattle, and for horses and sheep, the crop is cut at the boot to early-bloom stage when leaf is still plentiful. It is made into hay where a quick dry is possible, wilted and ensiled where it is not, or grazed in place behind electric fencing that moves with the regrowth. As a summer cover it smothers weeds and is later flailed into the soil as green manure.
Planted as a tall strip between vegetable rows, Sudan grass cuts wind speed and traps blowing soil without shading the crop beside it. It pairs naturally with a legume such as red clover or alfalfa, which fix nitrogen while the grass supplies bulk and structure.
On a sloping field or an eroding bank, a solid stand of interlaced stems holds the surface through the heaviest storms of the warm season. The root system reaches deep for subsoil moisture, so the cover keeps living when shallow-rooted annuals have already flagged.
Science & Biotechnology
The plant is a C4 grass, the same photosynthetic pathway that powers maize and sugarcane, which lets it keep fixing carbon through heat that shuts down a cool-season pasture. Stems are hollow and jointed, rising to roughly two and a half metres, and each carries a terminal loose panicle of small, often purplish-tinged spikelets. The leaf blade is broad with a pale, almost white midrib that runs its full length.
The single compound that dominates Sudan grass research is dhurrin, a cyanogenic glycoside stored in the leaf margins and young shoots. When tissue is damaged, or when a cold snap hits a still-growing stand, dhurrin breaks down and can release hydrocyanic acid, the so-called prussic acid that makes young or frosted growth dangerous to livestock. Forage laboratories therefore assay HCN potential and nitrate load before a field is cleared for grazing.
Uses & Benefits
The safe management rule is simple in principle: never turn animals onto a short, stressed, or frost-hit stand, and wait for regrowth to reach a usable height before grazing again. Mature stems carry far less dhurrin than fresh shoots, so a late, tall cutting is safer than an early, lush one.
Modern breeding lines track crude protein, in-vitro digestibility, and cell-wall lignin, because feed value drops as the stem toughens. Somaclonal variation through tissue culture has been used to screen for low-dhurrin types, and selection for darker, broader leaves improves both yield and palatability. The chemistry is measured, not guessed.
Growing from Seed
Sow once the soil has warmed and the risk of cold nights has passed; the seed is fine and needs a firm, clean seedbed. Drill or broadcast shallow, about one to two centimetres deep, press the bed, and keep the surface moist until the seedlings appear. Rows can sit fifteen to thirty centimetres apart depending on whether you want a thick mulch or a clean grazing lane.
Because the seed is small, do not bury it; a light covering and a roll to close the soil is enough. Keep the top few centimetres evenly damp through the emergence window, and thin the stand so individual plants are not crowded. A clinging crust after rain is the main enemy of an even emergence, so break it gently if it forms.
If you start in trays, move the young plants to the field when they stand about ten centimetres tall and carry three or four true leaves, not on any calendar date. Cut the first flush when stems reach roughly sixty centimetres and the new shoots at the base are already showing; that timing drives the second and third regrowth. Armyworms and aphids are the field pests to watch, with anthracnose and leaf blight in humid years.
Our Take
If you already grow a grain sorghum for the bird plot or the silo, this species is the leafy, cut-and-come-again cousin worth a row of its own; compare the two in the same season through Sorghum bicolor seed and Sorghum Grass seed, or pair the windbreak strip with Barley Grass seed Hordeum vulgare for a mixed warm-and-cool cover. Just respect the frost rule and the stand will feed your animals and hold your soil all summer.
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