The author is a grass-finishing cattle farmer in central Kentucky and an agricultural economist at the University of Kentucky.

Annual lespedeza can help bolster summer pastures, especially where fertility is lacking.

Annual lespedeza is a warm-season legume that has been largely forgotten about in the past half-century.

In 1919, two improved varieties of annual lespedeza were introduced: “Kobe” from Japan and “Korean” from . . . you guessed it . . . Korea. Both varieties produced significantly more forage than the common variety introduced in the mid-1800s, and they were quickly embraced by livestock farmers in the lower two-thirds of the eastern U.S. Annual lespedeza’s primary adapted range corresponds quite well to the Fescue Belt, but it is also found roughly 100 miles to the south, north, and west of the region.

The time period from 1930 to 1950 proved to be the high-water mark for this warm-season legume. The Missouri Agricultural Experiment Station estimated that nearly 6 million acres were being grown in that state in 1938, and Kentucky estimated that 5 million acres were being grown in The Bluegrass State that same year. The Kentucky officials claimed annual lespedeza was the most common forage crop planted at that time (USDA, Circular No. 536, 1939). Although detailed records are hard to find, it seems that these usage levels persisted for around a decade, then started to decline in the 1950s.

Annual lespedeza will germinate and start developing in early spring, but most of its production occurs in June, July, and August — perfect timing to help counter the summer slump. “Feeds and Feeding” (F.B. Morrison 1939) and the Illinois Agricultural Experiment Station Bulletin 416 (1935) stated it is as high or higher in feed value for cattle as alfalfa or red clover. Dairy farmers in the Fescue Belt relied on it quite heavily due to its quality and ease for making hay.

As with most forages, annual lespedeza grows best in highly fertile soils, but it is unrivaled where fertility is poor to fair. According to the USDA Farmers Bulletin No. 1724 (1934), “Lespedeza will grow on almost any type of soil. It does well on the sandy loam soils of the Coastal Plain, the clays of the Piedmont, and the limestone soils of Virginia, Tennessee, and Kentucky.” I have found poor drainage is about the only situation it doesn’t do well on.

A slump beater

These days, the most common way to use annual lespedeza is overseeded into cool-season pastures just like clovers. The key to seeding into an established sod is to target stands that are not overly vigorous. Therefore, stands that only produce well with fertilizer are prime candidates for annual lespedeza. Lespedeza will improve these soils over time and eventually work itself out of a job. At some point after fertility has been restored, grasses and clovers will out compete it. Think of annual lespedeza as a “bridge” legume when used in perennial pastures.

My favorite way to use this legume now is in a specialty pasture, essentially as a stand-alone summer annual that is double-cropped with winter annuals. This system was used extensively during the 1930 to 1950 period. On good ground, where annual lespedeza is not competing with an established sod, the production can be absolutely incredible from mid-June through early September. In the 1930s, the Kentucky Experimental Station estimated that on soils of medium fertility, 1,000 pounds of liveweight per acre can be grazed from June to October, while better fields could often carry twice this amount (USDA Circular #536, 1939).

Regardless of whether you are using it in perennial pasture or as a pure warm-season stand, having 20% to 35% of a farm in annual lespedeza will help balance out the forage supply since most of its production comes in July and August. Other summer annuals can produce more biomass but not necessarily more usable biomass for grazing. Sorghum-sudangrass is a perfect example. Its quality can go from good to poor in about a week, and you will typically lose a significant amount of the production while grazing. Conversely, the quality of annual lespedeza declines slowly over a three to four week period starting around mid-July. It gives you much more flexibility in utilizing it compared to any summer annual that I know of.

Annual lespedeza is also an inexpensive crop to plant. Seeding 10 pounds of seed per acre at $2.50 per pound and custom broadcast seeding at a cost of $7 per acre with no added fertilizer or herbicide puts the total planting cost at $32 per acre. With sorghum-sudangrass, you will likely have $25 to $30 per acre in seed, $20 for no-till drilling, and $50 to $75 in fertilizer for a total cost of $95 to $125 per acre.

A lost legume

During my extension meetings in Kentucky, I often ask who uses annual lespedeza. Usually, in a group of 30 to 40 farmers, one or two hands will go up, and they are typically some of the oldest in the group. Occasionally, no hands go up.

So, given all the advantages previously discussed, how is it that annual lespedeza has been largely forgotten about?

One reason is that the increased usage of commercial fertilizer and lime starting in the 1950s led to a shift to other forages requiring higher fertility levels, such as alfalfa and most of the productive grasses. A shift toward confinement feeding at this time, especially on dairies, meant there was less need for balancing the seasonal forage supply and forage demand. Thus, higher yields from alfalfa or red clover, even though most came in spring and early summer, were seen as superior to 2 to 4 tons of annual lespedeza per acre on the same ground where almost all came during the summer slump.

However, in the last two decades, there has been a significant shift back to more balanced year-round grazing. Given how well annual lespedeza fits that grazing model, it is still surprising more farmers aren’t using it.

Or is it?

From my perspective, the main reason that annual lespedeza is not making a resurgence in popularity is simply because it is not being promoted, or more accurately, its use has been largely discouraged. Read just about any contemporary publication that mentions this forage and you will see phrases describing it as “lower yielding.”

It may be low yielding on poor soil but will likely outyield anything else in those same fertility conditions. With good fertility, I have seen pure stands of annual lespedeza produce 3 to 4 tons per acre of dry matter available for grazing during the heart of the summer and then allow for winter annuals to be available for grazing in late winter and early spring.

Another impediment to its resurgence is that there is considerable misinformation regarding seeding and establishment. A typical recommended rate is 25 to 35 pounds of seed per acre, but my experience is that this is an overkill. I consistently get good to excellent stands broadcasting 8 to 12 pounds per acre. Possibly, seed used to be much cheaper on a relative basis, and thus the higher rates were seen as insurance. I do not know for certain, but with current seed prices, you want to optimize, not maximize.

A typical recommended seeding date is February to March. When first starting to use lespedeza, I seeded in February or early March as instructed. Some years I would have good stands and some years poor stands with not many stands in between. Unfortunately, it took me quite a few years to figure out what was going on. Annual lespedeza is a warm-season legume and has almost no frost tolerance once it develops its first set of true leaves (past the cotyledon stage). It will take a light frost, but temperatures around 28°F to 30°F will kill the seedlings.

If you broadcast in February and have a string of three to four days with highs in the 50s, say in early March, most of the seed will germinate. In Kentucky, the odds we will not have a hard frost from that point onward are slim to none. In situations such as this, the lespedeza stand would be wiped out. I now do not start seeding annual lespedeza until around mid-March and try to finish by early April but would not be afraid to broadcast up through mid-April. Adjust this window based on your growing season compared to central Kentucky.

In researching for this article, I came across the following from USDA Farmers Bulletin No. 1724 (1934), which backs up my experience: “In North Carolina and Tennessee, lespedeza is usually sown during February and March, and in Kentucky and Virginia, during March and the first half of April. Seed sown early may germinate during a period of mild weather, and later the young plants may be killed by freezing temperatures.” This was in the 1930s when Kentucky had real winters and likely had few stretches in late February and the first half of March when temperatures were in the 50s that would stimulate early germination of the seed.

A possible final reason we have not seen a resurgence is that annual lespedeza seed rarely comes inoculated. Inoculation is likely not necessary on pastures that have recently had the legume, but when introducing the forage back after 50 to 70 years of absence, it is cheap insurance. The correct inoculant is one for the cowpea-peanut family.

Reseeds itself

Based on the experience of a few farmers I know in Missouri, you can get two hay cuttings in a normal year on a pure stand if you get the first cutting by mid-July, when it will likely be around 15 inches tall, cutting it high enough to leave stubble with some leaves on it. In this situation, it is often possible to cut and bale the lespedeza on the same day due to the low-moisture levels in the leaves.

Whether pasturing or haying, it is a good practice to manage lespedeza stands so that they will set seed. In central Kentucky, Korean lespedeza will start setting seed in early September, with Kobe about two weeks later. Resting the lespedeza once it does this, or allowing at least a couple weeks growth after cutting for hay, will typically result in a natural reseeding. By late October, the seed should be well developed, and you can graze what remains.

Annual lespedeza has been a largely forgotten forage, and I hope that changes. But there are a few of us who are using it extensively and have come to appreciate its many advantages. I can’t imagine an easier warm-season annual forage to both establish and manage.