Marshall is a diploid annual ryegrass cultivar (Lolium multiflorum) that has served as the benchmark forage grass across the southeastern United States for decades. Released by Mississippi State University, it became the standard against which newer annual ryegrass varieties are measured in university trials. Its popularity comes from strong late-season forage production, reliable reseeding ability, and proven performance under grazing, though its slow early-season growth is a well-known trade-off that matters if you need winter feed early.
What Makes Marshall Different From Other Annual Ryegrass Varieties
Marshall is a later-maturing cultivar compared to varieties like Gulf and Surrey, which means it grows more slowly in fall and early winter but compensates with heavier yields in spring. In a multi-year study comparing annual ryegrass cultivars across different harvest dates, the difference was striking: at a January harvest, Surrey and Gulf averaged about 1,030 kg of dry matter per hectare, while Marshall produced only around 672 kg per hectare. By May, the pattern reversed. Marshall and another late-maturing cultivar, Jackson, averaged roughly 1,232 kg per hectare while Gulf dropped to about 929 kg per hectare. At the March harvest, all varieties performed similarly, averaging around 1,350 kg per hectare.1Crop Science. Cultivar and Environment Effects on Annual Ryegrass Forage Yield, Yield Distribution, and Nutritive Value
This maturity timing is important for practical grazing management. If your cattle need forage in December and January, Marshall alone will leave a gap. Pairing it with an earlier-maturing variety like Gulf or Surrey, or overseeding it alongside small grains like wheat, fills that window. By late winter and into spring, Marshall catches up and often outyields the early cultivars. A twelve-year evaluation of annual ryegrass cultivars across multiple locations found no trend for newer varieties to surpass Marshall’s total seasonal yield, confirming its staying power as a reliable all-around performer.2Crop Science. Multilocation Annual Ryegrass Cultivar Performance over a Twelve‐Year Period
Stockpiling Marshall for Winter Grazing
One management strategy that works well with Marshall’s growth pattern is stockpiling, where you let the grass accumulate biomass in late fall and then graze it through the winter without further growth inputs. A two-year study in the lower Midwest showed that stockpiled annual ryegrass yields ranged from 825 to 2,356 kg per hectare, with Marshall outyielding the other cultivar tested (Barmultra) on nearly every harvest date. Forage quality did decline somewhat from mid-December through mid-February, but even at its worst, fiber levels stayed low enough that the grass remained a high-quality feed source for grazing livestock.3Crop Science. Stockpiled Annual Ryegrass for Winter Forage in the Lower Midwestern USA
The fiber measurements in that study are worth noting for anyone evaluating hay or stockpiled forage quality. Acid detergent fiber never exceeded 252 g per kg, and neutral detergent fiber stayed below 455 g per kg. Those numbers translate to highly digestible forage, well above what you would expect from most stockpiled warm-season grasses at the same time of year. In a mild winter, the quality decline was even smaller, making stockpiled Marshall a practical bridge between fall and spring grazing seasons without the expense of supplemental hay.
Overseeding Into Bermudagrass and Other Warm-Season Pastures
The most common way Marshall gets used in the Southeast is as an overseeded winter annual into dormant bermudagrass or bahiagrass pastures. The idea is straightforward: your warm-season perennial goes dormant in fall, and you drill or broadcast Marshall ryegrass seed into the existing sod to keep the pasture productive through winter and spring. A study comparing sodseeding methods found that drilling ryegrass-clover mixtures into bermudagrass pastures with a conventional grain drill and broadcasting seed after light disking both produced similar total forage yields. The calves grazing these pastures gained an average of about 2.15 lb per head per day and produced roughly 460 lb of beef per acre, regardless of seeding method.4Journal of Production Agriculture. Effect of Sodseeding Method on Ryegrass‐Clover Mixtures for Grazing Beef Animals
That study also found that drilling a ryegrass-white clover mixture returned the highest net profit at about $93 per acre. Adding crimson clover to the mix increased total forage production and extended the grazing season further into April, though the additional seed cost slightly reduced the economic edge. The bermudagrass hay production in the following summer was unaffected by either seeding method, which is an important consideration since producers count on that summer hay crop. The practical takeaway is to use whatever seeding method is cheapest and most convenient on your operation.
Marshall has also been tested in combination with wheat overseeded into bermudagrass. A two-year grazing study in northwest Arkansas using Midland bermudagrass drilled with Caldwell wheat and Marshall ryegrass found that forage digestibility and crude protein were similar whether pastures were stocked continuously or rotationally.5Journal of Production Agriculture. Steer Performance and Nutritive Values for Continuously and Rotationally Stocked Bermudagrass Sod‐Seeded with Wheat and Ryegrass Combining wheat with ryegrass spreads the forage production window: wheat fills the early winter gap where Marshall is weakest, and Marshall carries the load into late spring as wheat matures out.
Grazing Management and Cattle Performance
A question producers frequently ask is whether Marshall performs differently under continuous versus rotational grazing. A direct comparison of Marshall and Surrey ryegrass under both systems found that individual cattle gains were not different between the two cultivars in either year of the study. Continuous grazing produced higher individual animal gains per head, but rotational grazing generated more total beef per hectare because it supported higher stocking rates. Rotationally grazed paddocks produced 403 kg of gain per hectare compared with 301 kg per hectare for continuously grazed paddocks.6PubMed. Comparison of Marshall and Surrey ryegrass for continuous and rotational grazing
The finding that Marshall and Surrey performed equally in cattle gains may surprise producers who assumed one cultivar would clearly outperform the other on pasture. The evidence suggests that management decisions, particularly stocking rate and grazing system, have a larger effect on total beef output than cultivar selection alone. If you are running a smaller herd and want maximum weight gain per animal, continuous stocking works. If you want maximum production from your acreage, rotational grazing wins, and it does so regardless of whether you planted Marshall or Surrey.
A more recent study evaluating beef steers on different annual ryegrass cultivars under continuous stocking found that dry matter intake as a percentage of body weight differed between some cultivars, with Marshall falling intermediate between the highest and lowest intake groups. The variation in intake hints that palatability or leaf-to-stem ratio may differ across cultivars, but overall performance differences remained modest.7Applied Animal Science. Performance of beef steers continuously stocked on different annual ryegrass cultivars
Nitrogen Fertilization for Maximum Yield
Getting the most out of Marshall requires attention to nitrogen timing. A three-year study planted Marshall ryegrass at 25 lb of pure live seed per acre and tested nine different nitrogen fertilization regimes, varying both the rate and timing of ammonium nitrate applications in fall and spring. The highest average forage yield came from applying 75 lb of nitrogen per acre split as 25 lb in fall and 50 lb in spring. Nitrogen fertilization consistently produced a slight yield advantage over interseeded legumes like clover, though the legume treatments still offered reasonable production with lower input costs.8Crop, Forage & Turfgrass Management. Impact of cool‐season legume interseedings or timed nitrogen applications on yield and nutritive value of annual ryegrass
The split application approach matters because Marshall’s growth curve loads heavily toward spring. Dumping all your nitrogen in the fall wastes a portion that will leach or volatilize before the grass can use it. Applying the heavier share in late winter or early spring coincides with Marshall’s peak growth phase and pushes yields higher where they count most. For producers who want to minimize purchased fertilizer, mixing Marshall with a legume like crimson clover or white clover is a reasonable alternative that trades a small yield reduction for lower input costs and some nitrogen fixation benefit that may help the subsequent summer crop.
Seed Characteristics and Establishment
Reliable stand establishment is one of Marshall’s practical strengths, but seed quality varies from year to year and lot to lot. A three-year evaluation of annual ryegrass cultivar seed characteristics found that single-seed weight ranged from 1.8 to 4.8 mg across cultivars and years, and germination ranged from roughly 78% to 98%. The number of pure live seeds per square meter at a standard seeding rate varied considerably, from 675 to over 1,500. Seedling weight was highly correlated with seed weight at each planting depth, meaning heavier seeds produced more vigorous seedlings.9Grass and Forage Science. Seed variation among annual ryegrass cultivars in south‐eastern USA and the relationship with seedling vigour and forage production
The practical implication is to buy seed with a recent germination test and, when possible, to select lots with heavier seed weight. A bag of Marshall with 95% germination and robust seed will establish faster and compete better with weeds than a cheaper lot sitting at 80% germination with lightweight seed. Given Marshall’s already-slow early growth, anything that delays stand establishment compounds the winter forage gap.
Reseeding and Seed Production
One of Marshall’s appealing traits for low-input systems is its ability to reseed itself if allowed to mature before spring grazing ends. A study examining grazing termination dates and their effect on annual ryegrass seed production found high spike densities of over 1,250 spikes per square meter when grazing was stopped by late April, though seed yields were relatively low at about 49 g per square meter. The 1,000-seed weight was a healthy 3.12 mg, and all cultivars tested exceeded the 500 seedlings per square meter target needed for volunteer reestablishment the following fall.10Crop Science. Grazing Termination Date Influence on Annual Ryegrass Seed Production and Reseeding in the Southeastern USA
The catch is that weather strongly influences whether reseeding succeeds. In a subsequent year of the same study, a very dry May followed by heavy June rainfall reduced the 1,000-seed weight to just 1.37 mg, less than half the previous year’s value. Lightweight seed germinates poorly and produces weaker seedlings, which means a bad seed-fill year can lead to a thin volunteer stand the following fall. Producers who rely on natural reseeding should plan to have purchased seed on hand as insurance, or at least monitor the seed crop before assuming the pasture will reseed itself.
Disease Considerations
Crown rust and gray leaf spot are the two diseases that most commonly affect annual ryegrass in the Southeast. Marshall has moderate susceptibility to both, and in warm, humid springs the rust can be severe enough to reduce forage quality and palatability. Newer cultivars have been bred specifically to address this weakness. FL PE, a later-maturing diploid released through recurrent selection at the University of Florida, went through eight cycles of selection for resistance to both crown rust and gray leaf spot and showed excellent rust resistance in field trials.11Journal of Plant Registrations. Registration of ‘FL PE’, a Later‐Maturing Diploid Annual Ryegrass
If crown rust is a recurring problem on your farm, especially in the Gulf Coast states where the disease pressure is heaviest, trying a rust-resistant cultivar like FL PE alongside or instead of Marshall is worth considering. Marshall remains the workhorse, but it was not selected for disease resistance, and the breeding progress in newer varieties has been real on that front.
Using Marshall as a Cover Crop
Beyond livestock forage, Marshall ryegrass and other annual ryegrass cultivars have value as winter cover crops in row-crop systems. A study integrating winter annual forages into no-till corn silage production found that cover crops (including annual ryegrass) produced three to five times more root biomass than bare fallow, tripled soil microbial biomass in the spring, and increased particulate organic carbon concentrations by 23% in the top 15 cm of soil.12Agronomy Journal. Integrating Winter Annual Forages into a No‐Till Corn Silage System
Those soil health benefits come on top of the erosion control that any winter cover provides. For row-crop producers who also run cattle, Marshall planted as a cover crop can serve double duty: graze it through winter and early spring, then terminate it before planting the summer cash crop. The nitrogen scavenging from ryegrass roots also helps reduce nitrate leaching, which is increasingly on the radar in watersheds with nutrient-management concerns.
Baleage and Preserved Forage
Not all Marshall ryegrass gets grazed directly. Some producers harvest it as baleage, which is forage baled at higher moisture content and wrapped in plastic to ferment like silage. A study examining baleage made from a mixture of cereal rye, annual ryegrass, and tall fescue found that initial bale moisture had the strongest influence on fermentation characteristics. Wetter bales produced more fermentation acids and lower pH, while drier bales retained more water-soluble carbohydrates and starch. Neutral detergent fiber was slightly higher in the unfertilized control bales compared with those receiving poultry litter, but overall the nutritive value differences between fertilizer treatments were small.13Crop, Forage & Turfgrass Management. Application of poultry litter and moisture effects on rye–ryegrass–fescue baleage
The key lesson for making ryegrass baleage is moisture management. Ryegrass has a high water content at cutting, and getting it to the right moisture range for baling, typically around 50-60%, requires adequate wilting time. Baling too wet leads to poor fermentation and potential spoilage; baling too dry means inadequate fermentation to preserve the forage. The window can be tight in a spring with frequent rain, which is exactly the kind of weather ryegrass tends to thrive in.
Annual Ryegrass as a Weed Problem
It is worth knowing that annual ryegrass is not universally welcomed. In Australian broadacre cropping systems, herbicide-resistant annual ryegrass is the most damaging weed, thanks to its abundance, high seed production, and tendency to outcross and spread resistance genes. Bioeconomic modeling has shown that integrated weed management programs combining crop rotation, competitive crop varieties, early sowing, and weed-seed-control practices can substantially reduce the economic cost of managing resistant ryegrass, with an 80% effective weed-seed-control program cutting the cost of dealing with glyphosate resistance by up to AUD 18 per hectare.14Crop Protection. From resistance to resilience: A bioeconomic evaluation of integrated weed management of glyphosate-resistant ryegrass in dryland cropping systems
In the southeastern US context, Marshall ryegrass’s tendency to reseed is a feature for pasture managers but can become a headache if the ryegrass volunteers into a summer crop field where it is not wanted. The same vigor and seed production that make Marshall convenient for low-input grazing systems make escaped plants difficult to manage in row crops, especially if herbicide-tolerant biotypes develop. Producers who rotate between ryegrass pasture and row crops should be deliberate about termination timing and monitor for volunteers.
Climate Resilience and Future Breeding
Ongoing research is examining how Marshall will perform under changing atmospheric conditions. A controlled-environment study compared the Marshall cultivar at both its normal diploid chromosome level and an induced tetraploid level under elevated carbon dioxide concentrations. Total biomass increased by 44% when CO₂ was raised from 540 to 800 ppm, driven by greater aboveground growth regardless of genetic background. At the diploid level, a wild-type annual ryegrass had a lower leaf-to-stem ratio than Marshall, suggesting potentially lower forage quality, but that difference largely disappeared when both were converted to tetraploids.15bioRxiv. Leveraging Crop Wild Relatives and Ploidy Level for Climate-Resilient Annual Ryegrass
The biomass boost under higher CO₂ sounds like good news, but forage quality often declines as plants grow faster, shifting more resources into stems at the expense of leaves. The tetraploid results are intriguing because they suggest that manipulating chromosome number could help maintain forage quality even as atmospheric CO₂ rises. This is still early-stage research and has not been validated under field conditions, but it signals that breeders are thinking about how cultivars like Marshall will need to adapt in the decades ahead. For now, Marshall remains the standard it has been for years: a dependable, late-maturing annual ryegrass that rewards patient management and pairs well with complementary forages to fill its early-season gap.