BEETING WEEDS IN NATIVE GRASS PLANTING

The best strategy for dealing with weeds in native grass plantings begins in the planning stages. Unfortunately, weed competition is not always considered when planning. In that event, you must figure out what to do to keep weeds from getting the best of your native grass planting. It is a fine line to walk. From the wildlife perspective weeds are good because they provide habitat for insects, food for growing chicks, cover for protection from predators and weather and later in the season, seed, many times important for winter survival. Too many weeds and the success of your planting is in jeopardy.

On clean till or conventional seed beds it is best to prepare the seed bed early in the season and continue to disc every couple of weeks or so as each new flush of weeds comes on. It is important, however, that each subsequent discing is shallow. If you continue to deep till you only succeed in bringing up more weed seeds buried within the soil, never getting ahead. Another advantage of this method is that it forces you to plant late in the season. It has been my experience that the later the planting the fewer weed problems you encounter and those that do germinate, typically do not create any establishment problems. In fact, from the wildlife perspective, late plantings provide good brood habitat for late nesting quail. By late planting I mean primarily the month of June. Plantings can be made as late as the middle of July if adequate moisture exists. If it's July 10 and you are in the middle of a 2 week drought, don't plant. However, if you've been getting regular rainfall and soil moisture is adequate, go ahead and plant.

On no-till plantings, since you're having to use herbicides for burn down, go ahead and use a herbicide mix including Plateau herbicide for residual weed control. Generally, speaking weed response to late no-till plantings is similar to late clean till plantings. With that in mind, if you do not use Plateau herbicide you can expect less weed competition with late plantings compared to early plantings.

What do you do if you've already planted and weeds are becoming a problem in your native grass planting? Mowing is probably the most universally applicable method of weed control. Best results are obtained with two, three or more mowings during the first growing season. Scout your field during the establishment period to be familiar with the weed growth and pressure. The best approach is; as weeds get 2 to 3 times taller than the new native grass and forbs, mow above the new seedlings. As the season progresses your mowing height will increase as the new native grasses and forbs begin to grow upward. Eventually, the native grasses and forbs will be taller than is possible to avoid clipping with the mower. If you have kept up with your mowing during the season, don't worry about clipping off the top few inches of your new plants. In any event, do not mow closer than 8 to 12 inches above the ground.

If weeds have completely overgrown your new seedlings before you've gotten a chance to mow, it may be better to not mow at all. The foremost concern, particularly a problem with rotary mowers, is the accumulation of litter in windrows. The thick mat of dead vegetation caused by a rotary mower will choke out and kill any new seedlings eliminating any chance of establishment, whereas the new seedlings stand somewhat of a chance without mowing. As long as they're alive they at least have a chance of making it. Native grasses also, under heavy, tall weed pressure, respond by growing as tall as necessary to compete, thereby being susceptible to clipping when the weeds are mowed. A good example is when foxtail becomes a problem and grows 3 feet or taller, native grass seedlings, though very spindly will grow 18 inches to 2 feet tall with all leaf area above 18 inches. When mowed at 12 inches a sequence of negative reactions begin. Because of their tall spindly growth their leaves get clipped off leaving nothing but the stem causing the plant to pull growth energy from the roots that haven't had a chance to store any carbohydrates yet, weaking the plant, further reducing it's chance of survival. I've also seen new seedlings, exposed by a recent mowing scalded by the hot August sun, killing them.

The best strategy is mow early and mow often or don't mow at all.

Herbicides can be effective in some cases. When planting grasses exclusively, a broadleaved herbicide such as 2,4-D can be used to control weeds. The problem is that most broadleaf herbicides do not carry a label for use on native grasses. In that case the user assumes all risks. Pursuit, one product I am familiar with, does carry a supplemental label for CRP. I'm sure there are others. Consult with your local Ag-chem dealer. By now, I'm sure you've probably heard about Plateau herbicide, at least if you've read anything I've written. Plateau does an excellent job of controlling weeds, both grassy and broadleaved, in labeled native grasses. To get good control of most weeds 8 to 12 ounces per acre is recommended.

When planting forbs exclusively, a grass herbicide such as Fusalade, can be used to control grassy weeds but will have no effect on broadleaf weeds. Again I am sure there are other brands. Consult with your local Ag-chem dealer. A word of caution, unless you have experience with a particular herbicide on a specific species be very careful. Even though Fusalade is a grass herbicide I have seen it do considerable damage to some forbs. Plateau can also be used on labeled forbs, however at a much lower rate than on labeled grasses. (It is important to recognize the phrase "labeled forbs". Many, but not all forbs are tolerant to Plateau herbicide. Some are more tolerant of higher rates than others. Consult the Plateau label for a list of labeled forbs.) The maximum rate of Plateau on forbs should not exceed 4 ounces per acre. Problem is, at that rate you will not get much control on perennial grasses or broadleaves. Four ounces per acre will provide good control on foxtail and crabgrass, fair control on annual braodleaves but limited action, if any, on perennial grasses and broadleaves.

As I mentioned before, the best option for weed control in a mixed planting is to plan ahead and use Plateau at planting time. Though using a lower rate than for a pure grass stand, the weed control will be just enough to help suppress the weeds long enough for the native grasses and forbs to get a foot hold and be competitive. Using this method you will get the best of both worlds. Plateau at 4 to 6 ounces per acre will provide just enough control to help with establishment yet allow enough weeds to grow to provide good brood cover for wildlife.

Dealing with weeds in a mixed stand after planting is a real challenge. There really aren't any herbicide options out there that can do it all, control all unwanted perennial grasses and broadleaves, yet not harm the desired species. Especially if you aren't dealing with the weeds until they have become a problem. If your planting has gotten to this point you need to give it some serious thought and make some tough decisions. Are the weeds bad enough that they threaten the establishment of your stand? What percentage of the field has a weed problem? Do the weeds cover the entire field or are they only in isolated areas? Once you can answer these questions you have the information necessary to answer a few more to make a final decision.

Is the weed infestation bad enough you need to sacrifice part of your planting? It's a tough call to make but one that sometimes needs to be made. If the weedy problem is too bad it makes sense to use a herbicide to control the problem. You may have to use a broadleaf herbicide such as 2,4-D or Remedy to control the problem, sacrificing your forbs but saving your grasses. Once the problem broadleaf is under control you can then reintroduce the forbs. If there are only isolated areas of the field infested with the problem plant then spot spraying may be your answer. You can spare most of the planting and only have to redo part of it.

Timing of application might be your answer. When dealing with cool season grasses such as fescue in a native grass planting, a dormant season application of Roundup can get control over the fescue while not harming the native grasses. A dormant season application can be made anytime the desirable plants are dormant and the problem species is actively growing. Watching the growth very closely might even allow you to control certain broadleaves or legume species while saving others. Keeping close track of the growth is critical however.

Getting a handle on weeds is sometimes a real challenge. As I said in the beginning, the best way to deal with weeds is in the planning stages. Plan to use a herbicide and or technique that will reduce the likelihood of weed problems. Be sure to also choose the correct native grasses and forbs for your area so that they can be the most competitive. If nothing else, mow early, mow often and mow high. Don't get discouraged, weedy plantings can take several years to develop. Have patience and give it time. Most of the time 3 to 5 years from planting you can't tell the difference between problem plantings and and those that weren't.