Author: J. Wayne Fears
Source: Whitetails Unlimited Magazine

Why all the sudden interest in subterranean clover, commonly called subclover, I can’t explain. However, due to the number of questions I have received from readers inquiring about subclover for deer food plots, I felt we needed to give the plant some coverage, especially its strong and weak points. Due to its somewhat limited range, it is one of the lesser-known clovers planted in deer food plots and is not used in many food plot seed mixes.

Subclover History

Subterranean clover gets its name from the fact that it produces its seed near the soil surface. It is native to Europe, Northern Africa, and temperate Asian countries. It was introduced into Australia and cultivated there as a pasture crop beginning around 1889. Introductions were made to the United States by the Department of Agriculture in the early 1920s. It is now grown as a pasture crop on the West Coast from British Columbia to southern California, as well as on the East Coast and in the Southeast.

Description

The seed of subclover is larger than most cool-season clovers.

Subclover is a cool-season annual legume. It is usually planted in the fall following a rain, and growth is rapid through the winter months. It grows in densely matted clumps that are 6 to 14 inches tall and spreads through rootless runners reaching up to 3 feet in length. The leaves are alternate and sometimes clustered from the lack of a stem. The leaflets are usually grown in threes. The flowers of subclover and seed development occur below the leaves. A flower cluster may contain up to seven blossoms, but three or four is more common. The flowers are white or white with pink veins.

Subclover is self-fertilizing, so there is no need for insect pollination. After fertilization, the flower develops a burr which turns downward. The burr is eventually pushed under the soil surface. Heavy deer feeding can occur at this time without reducing seed production. This process is what makes this species unique among clovers and thus the common name. In fact, subclover does best when heavily fed upon by deer.

The seed is the largest of any cool-season clover and is dull purplish-black to black, except for the white-seeded cultivars of T. yanninicum. Like other legumes, subclover produces N-fixing nodules on its root system.

Range

Subterranean clover thrives in USDA plant hardiness zone 7 or warmer. It does best where the summers are hot and dry and the winters cool and wet, with temperatures above 10 degrees. This clover is particularly popular in western states, especially along the Pacific Coast. Its use is increasing throughout the deep South and the Mid-Atlantic states, where it is planted as both a food and cover crop for wildlife. Due to its shade tolerance, it is planted with pine timber to raise the nitrogen level of the soil for better wood production. Also, it’s good to plant in food plots with trees in the plots.

In other areas, subterranean clover is rarely grown for livestock because it usually requires mild winters to produce quality forage, but it is still a useful plant in food plots, especially when mixed with warm-season perennials such as ryegrass, cool-season winter grains, and vetch.

Planting

	Preparing a good seedbed is important for a good stand of subclover.

Subclover is best adapted to well-drained, sandy loam or clay soils. It requires a pH range of 5.5- 7.5; optimum pH is 6.5. It grows best in full sun but is tolerant of up to 50% shade. Recommended food plot planting time is fall and spring when nighttime temperatures are consistently below 65 degrees, but no lower than 40 degrees. In the fall, plant from September to October before rain. For a spring and summer food plot crop, plant after the last frost.

Starting with a clean, firm, prepared seedbed, pre-inoculated subclover seed can either be  broadcast or drilled. To broadcast, use 15-20 pounds per acre and then lightly disk or drag to cover the seed to no more than a half-inch. To drill, use 10 pounds per acre and plant a half-inch into the soil. Subclover can also be over-seeded into permanent sod at 8 pounds per acre. Under optimum conditions, subclover seed will germinate in 5 to 7 days. It has been proven to reseed itself if managed properly.

To increase the potential production of subclover, the seedbed should be fertilized with phosphorus and sulfur. Since legumes such as subclover are already heavy in nitrogen, most studies suggest 250 to 300 pounds of 0-20-20 fertilizer per acre each fall.

If subclover is planted in pine timber, abandoned logging roads, or grown-over food plots, it may be necessary to burn off ground plants and leaves before broadcasting the seed and fertilizing. Good seed-to-ground contact is necessary. Due to the small amount of sunlight hitting the forest floor and the heavy leaf fall each autumn, subclover does not do well when planted under mature hardwoods.

Due to its shade tolerance, Subclover can be planted in pine stands, abandoned logging roads or food plots with trees standing in the plot.

For food plots subject to erosion, subclover is an excellent erosion fighter due to its large, dense mat of above ground stems, petioles, and leaves, and its large, fibrous root system. Its full potential for erosion control is usually achieved in the second season after planting, when populations are fully established.

Some of the most popular varieties of subclover are Mount Barker, Woogenellup, and Tallarook. Mount Barker is actually an Australian native that is particularly popular in the southern part of the U.S. because of its dual use in food plots and timber stands.

Subclover does not do well as a single food plot crop. It does best as a deer food plot crop when planted with cereal crops such as vetch, rye, or wheat. It can be used in food plot seed mixes such as 10 pounds of subclover, 25 pounds of cereal rye, 30 pounds wheat, and 3 pounds of white clover.

Pros & Cons of Subclover

The biggest drawback to planting subclover in many areas of the U.S. and southern Canada is the limited range of the legume. It cannot tolerate cold weather. Because of this, seed can be hard to find in many regions.

Subclover does not do well when planted alone. It needs to be planted with other cool season crops to be successful. It does not tolerate droughts or poor drainage.

Also, to get natural reseeding, subclover requires heavy grazing by deer, or burning or mowing in late summer.

On the plus side, when subclover is planted properly within its range, it’s shade tolerant, nutritious, can withstand heavy grazing, and can help with erosion control.

So there you have it. Subclover can be a good food plot legume where it is suited, but in the wrong place, it will not be the crop of choice.

 

Editor’s note: This plant may become weedy or invasive in some regions or habitats and may displace desirable vegetation if not properly managed. Please consult with your local NRCS Field Office, Cooperative Extension Service office, state natural resource, or state agriculture department regarding its status and use before including it in your wildlife management plan.

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