Figure 19. Excellent control of johnsongrass and broad-leaved weeds (left) by using a rope-wick applicator on this young Old World bluestem stand. The strip to the right of center was untreated.

Figure 20. 'Plains' bluestem being smothered by too much mowed residue.

Figure 21. First-year 'Plains' bluestem grazed three times for grassy weed control (left), which resulted in good establishment and good, clean production the second year (right).

Rope wick, carpet wick, and cotton-wrapped tube wick applications can be used in many situations to apply herbicides for control of broad-leaved and grassy weeds where usual sprayer equipment or sprayed herbicides cannot be used (figure 19). These applicators can be used on very young Old World bluestem seedlings or before seedling emergence.

Some uses for rope-wick applications are control of johnsongrass, or other grasses taller than Old World bluestem, by using glyphosate (Roundup); control of broad-leaved weeds taller than Old World bluestem by using any proper postemergencence herbicide such as 2,4-D or dicamba; and control of broadleaved or grassy weeds where drift and volatility control are a problem.

Mix the herbicide and water in a one-third to two-thirds ratio (one-third herbicide). Drive slowly (2 to 4 miles per hour) and wipe the weeds to be controlled. Carry the applicator above the Old World bluestem, if it is present, and in the weed canopy to get a good wiping action. Wipe the area twice, with the second application directly opposite from the first in the same tractor tracks. Read the herbicide directions for other mixture ratios.

Results are not as good as that with excellent full-coverage spraying, but they are definitely good. The technique controls broad-leaved and grassy weeds and releases Old World bluestem seedlings from competition. Repeat applications may be needed. Rope-wick applicators require less chemical, little of it reaches the soil, and because there are no small droplets, there is no spray drift and you can use less.

If stock are unavailable or other grazing restrictions are imposed, mowing for weed control or hay is the next best thing. When the grassy competition or broad-leaved weeds reach at least 8 inches, mow to about a 3-inch stubble. Allow regrowth and remow as needed at the weedy height indicated. Do not mow after August 15.

Avoid mowing and leaving large amounts of residue that completely cover the Old World bluestem plants (figure 20) because they will smother. It is better to mow earlier or bale and remove the residue. If mowed residue is thick and must be left on the area, do the mowing with a sickle mower and leave the residue lying flat, which will leave less full coverage and more openings in the mowed residue for the bluestem to regrow through. If there is sufficient yield, hay the residue. Stock will eat almost anything as hay.

Mowing is also done for broad-leaved weed control where 2,4-D or other herbicides cannot be used. Mow at the top of the major Old World bluestem growth to top off broad-leaved weed growth, but be aware that 2,4-D or other herbicide weed control is far superior. In a government program (CRP) that disallows grazing or haying, frequent mowing is the only logical control.

Some grassy weed competition can be controlled with certain seedbed preparation techniques. Refer to comments in the seedbed preparation, seedbed weed control, and no-till sections.

There are no selective herbicides approved for control of the numerous grasses that often invade establishing Old World bluestem. The only postemergence control is use, which is the lesser of two evils in this case. The objective is to save and improve the stand. Production comes later.

If palatable grasses are a problem, excellent control is possible by quick, uniform grazing. Stock the area so it will be grazed off in one week or less, one day being ideal. This technique may require at least 30,000 pounds of stock density per acre. Remove the stock and allow regrowth. Old World bluestem will regrow, add tillers, and become more robust with each grassy weed use. Several grazings may be needed the first season.

Without soil disturbance, grassy weed competition is usually much less the second year and beyond. Avoid grazing after about August 15. Grassy weeds such as crabgrass, sandbur, and johnsongrass usually regrow little after this time. This procedure has been used many times with excellent results (figure 21). Avoid letting cattle trample young stands in the mud or loose sand. This procedure may require the development of a rotational grazing unit.

Use of first-year stands is based entirely on growth produced (excepting consideration of government programs) but they can often be properly used sometime during the first growing season (figure 12).

Old World bluestem should not be used the first year until forage volume and height are sufficient, seed have shattered, or there has been a killing frost, as described below. The plants should be well rooted into the secondary root stage. Remember, use also helps control weeds.

If Old World bluestem produces 1 ton (thick and about a foot high) of forage by July, it is then acceptable to use it. This use should be moderate, quick, and uniform so early uniform regrowth can occur. Never graze it short; try to keep residue height at 3 to 6 inches through high-density rotational grazing. Midsummer first-year Old World bluestem use is highly recommended when growth is 1.5 tons (thick and knee high) or more per acre by July or early August. Huge accumulations of forage can deteriorate stand development and total production. To repeat, do not graze young stands short, but try to keep residue heights at 3 to 6 inches.

If Old World bluestem produces less than 1 ton by July because of thin stands, periodic drought, or the like, moderate use can occur after mature seed have shattered. This use should be quick and uniform so uniform regrowth can occur. Haying or grazing in this case helps tread in seed for future volunteer stands, and use encourages retillering and further development. Adhere to the same residue heights as above.

If the stand produces poorly or doesn't mature much seed, then don't use it until after a killing fall freeze. Early winter graze-off is best done gradually rather than in a few days. Graze all stands, regardless of production, the first winter to remove residue, help tread in seed for future volunteer stands, and encourage added spring tillering.

If a midsummer use is possible, hay the first production rather than graze it, which allows quick uniform use, controlled residue height, and uniform regrowth. Haying also controls some weeds. All use in this case should leave a 3- to 6-inch stubble. Hay or graze young stands when soil moisture is adequate for good recovery after use.

Monitor seedling pull-up, especially on sandy soils, and trample damage on all soils. Stop grazing if the stand is being reduced.

Don't use first-year Old World bluestem under severe drought or during late summer to frost (August 15 to November 15) under any circumstances.