Fight The Summer Slump With Annual Lespedeza
LINDA GEIST
MOUNT VERNON, MISSOURI
Tall fescue is the backbone of most grazing systems across Missouri, and for good reason, says Caleb O’Neal, University of Missouri Extension field specialist in plant science.
Tall fescue is a tough, productive, and well-adapted grass for the region’s climate. “However, even the best cool-season forages share a predictable weakness: the summer slump,” says O’Neal.
During hot, dry summer months, tall fescue growth slows, forage quality declines, toxicity levels rise and overall forage availability can become limited. Annual lespedeza is a forage option that offers a simple, low-input way to help fill this summer slump while improving overall pasture performance and soil health, says O’Neal.
What is annual lespedeza?
Not to be mistaken for the perennial weed sericea lespedeza, annual lespedeza is a warm-season annual legume that pairs exceptionally well with cool-season grasses like tall fescue
Its primary growth begins in June, when fescue growth naturally slows or after the first hay cutting is removed. Annual lespedeza can provide quality forage during July and August, when many fescue pastures are under the greatest stress.
Although annual lespedeza is not typically considered a high-yielding forage, its forage quality is among the highest, says O’Neal. Forage tests often show protein content and total digestible nutrients comparable to alfalfa.
Rather than renovating Kentucky 31 fescue pastures, adding annual lespedeza complements existing stands by extending the grazing season, improving forage quality and diluting the effects of endophyte toxicity during the most challenging months of the growing season.
A low-input forage option
One of the greatest advantages of annual lespedeza is its ease of establishment and adaptability, O’Neal says. Unlike many legumes, it can be productive on soils with pH levels as low as 5.0 and on sites with marginal fertility.
While productivity improves as soil fertility increases, annual lespedeza can be suppressed by more competitive species when even moderate rates of nitrogen fertilizer are applied, so apply fertilizer cautiously in pastures where annual lespedeza is expected to persist.
Annual lespedeza’s ability to be productive on poor soils makes it especially well-suited for hill ground, thin soils and rented pasture acres where fertilizer inputs may not be economical. As a nitrogen-fixing legume, annual lespedeza can also improve pasture performance without requiring significant financial investment.
Establishment and management
Annual lespedeza can be frost-seeded into existing pastures in late winter or broadcast in early spring. As with all forage establishment, seed-to-soil contact is critical, so in pastures with heavy residue, dragging a light harrow after broadcasting may be necessary. Drilling seed in late March through early April is also an effective option when equipment is available.
To maintain annual lespedeza in future years, it is essential to allow the plants to reseed. Grazing animals should be removed, and hay production paused, by late August on seeded fields. Allowing the stand to rest until the first killing frost enables plants to flower and set seed for the following season.
Annual lespedeza varieties
There are many excellent varieties that can be found, but most commercially available annual lespedeza seed is sold as either Kobe or Korean lespedeza, O’Neal says. While both species are useful, key differences should be considered.
Kobe lespedeza has smaller leaves, a lower growth habit and later maturity. It produces flowers closer to the ground, which allows for greater grazing tolerance, and it performs well on poor soils.
Korean lespedeza generally produces higher yields, grows taller and is better suited for rotational grazing or hay production. It flowers and sets seed earlier than Kobe lespedeza but is more susceptible to disease pressure and heavy grazing.
Selection should be based on management goals and site conditions, O’Neal says. For low-input pastures where persistence is a priority, Kobe lespedeza is often the better option. For producers aiming to maximize summer forage production under managed grazing or hay systems, Korean lespedeza may be the preferred choice.
A practical tool for summer forage gaps
“Annual lespedeza is not a single solution for overcoming the summer slump, but it is a proven and practical tool that fits well into many grazing and hay systems,” he says. “When thoughtfully integrated into a cool-season forage base, it can increase summer forage availability, improve soil fertility, enhance animal performance, and do so at minimal cost.” ∆
LINDA GEIST
UNIVERSITY OF MISSOURI