Safety, cover, and high-quality forage are key for whitetail management. Provide those features and you will immediately improve the huntability of your food plots and how frequently deer utilize the space. However, you must also consider crop height, cover screens, protein levels, and soil nutrition when choosing warm and cool-season plantings. Sunn hemp checks all those boxes.
Sunn hemp is a sub-tropical, shrubby, branched legume native to India that doesn’t get much attention in the hunting space, yet it thrives in the Southeast. By no means is this warm-season annual a silver bullet, but it’s certainly an excellent addition for habitat diversity, wildlife security, protein forage, and soil health. It’s been a staple at our farm for seven years.
The towering, thick cover is my favorite aspect of the legume. Personally, I love losing sight of deer when they browse through a field. You limit shot opportunities, but you also absolutely increase daylight movement. You can use a tractor to create openings by mowing shooting lanes or maintaining an overall lower height. Those objectives depend on your plot size and stand setup.
Deer will feed on the bright green elliptical leaves and tender budding tops. The stems will continue to grow back after being snipped off until the first frost, which is usually early November in the Southeast. Once the stem becomes thick and fibrous it’s less palatable. Deer will then eat every remaining leaf up to 3 or 4 feet off the ground.
Not much testing on sunn hemp exists, but the estimated crude protein levels exceed 25% to 30% per the National Deer Association. As a comparison, in Wildlife Food Plots and Early Successional Plants, Dr. Craig Harper reports that soybeans offer 36.5%. Crude protein content is imperative for land stewards to understand for a healthy, well-balanced herd. For instance, the Mississippi State University Deer Lab recently posted the following crude protein requirements for deer: the late gestation period needs 12%, a lactating doe needs 14% to 16%, antler development requires 16%, and fawns post-weaning to 1.5 years old demand 17% to 25%.
Based on these figures, sunn hemp and soybeans are outstanding supplemental food plot options for whitetails. Combined with prescribed fire and early season disking, you’ll not only observe more deer during the fall but will also improve herd health. The latter should be the ultimate goal for conservationists and land managers. Food diversity will attract more deer on your landscape, especially during high-pressure hunting seasons.
According to Anne C. Randle’s article Sunn Hemp: Forage and Soil-Building Superhero, “Sunn hemp possesses many soil-building traits, including high rates of biomass production—over 20 percent greater than crimson clover and hairy vetch in research trials. It is not only resistant to plant root nematodes but actively suppresses them. In as little as 60 to 90 days it can produce 120 pounds of nitrogen per acre and can suppress weeds up to 90 percent.”
Those are staggering and impressive stats when considering seed and fertilizer costs.
Hemp grows well in sandy soils and is relatively drought-tolerant which is a huge advantage in the Southeast. It also flourishes in hot, humid areas with a heavy taproot and a well-formed root system. The legume can minimize soil erosion, conserve water, and recycle plant nutrients from the subsoil to the topsoil.
Depending on your goals, sunn hemp may need more maintenance than most annual food plots as it grows about an inch per day until maturity. This is a stark difference between soybeans and most warm-season wildlife plantings. It may take deer a little bit of time to focus on hemp but they will find it the first year. The activity will continue to pick up year after year. At my farm in South Carolina, deer have been hammering the succulent stem tops since the second planting year.
I suggest starting off with several test sites and evaluating results before planting in year two. Utilizing the plant for cover screens is ideal around larger fields or wide-open areas to direct the flow of game travel. Cowpeas are perfect to mix in as sunn hemp stalks provide structure for the vines to wrap around and expand.
Early sprouts are highly attractive for deer and could pose a problem if the crop isn’t established first. Monitor, and if necessary, rope off plots or add milorganite fertilizer to keep deer at bay until the plant reaches 2 to 3 feet. At that point, the plant will become browse-tolerant as long as your area receives sufficient rainfall. Post-season, mow the standing stalks and let the organic matter break down into the soil bed.