I have a 5 year old ginseng plot that has become overrun by stilt grass(packing grass). Stilt grass is an annual and grows from the ptrvious years seeds. Can I use \"Preen\", the comercial preemergance, to prevent the stilt grass from germinating while not harming the established ginseng?
I am not sure about using \"Preen\". I would think it would damage the ginseng. Is there a chance you could pull it by hand before it reseeds itself this year. Then do this every year until it is eventually \"weeded out\"?
As with all invasive plants, prevention is the best method of control. Avoid transferring seeds of stilt grass to new locations on clothing or otherwise. As stilt grass is a weak-rooted annual, new or relatively small infestations can be pulled up by hand. Effective hand-pulling will require follow-up visits for several seasons to remove plants emerging from seeds stored in the soil. Larger populations can be mowed or weed-whacked, which should be done when plants are mature but seeds have not set. Mowing before seeds have set will prevent plants from sending up new shoots and making new crops of seeds. For more extensive infestations, a systemic herbicide (i.e., glyphosate), or an herbicide specific to annual grasses may be a better choice. If applying herbicides to plants in wetland areas, use a product designed for use in wetlands. Use herbicides responsibly and follow manufacturer?s directions. Contact the Maine Department of Agriculture for information on restrictions that apply to the use of herbicides. Consult a licensed herbicide applicator before applying herbicides over large areas.
Control Level Diagnosis: Medium-high priority. Microstegium vimineum has spread throughout the eastern United States and continues to expand its range. It establishes quickly in disturbed areas, but is effectively kept at bay in undisturbed areas. Although the bigger threat comes once established, it can then quickly dominate, so quick control is important.
Control Method: Prevention of spread is the best control method. But where plants have already become established fast action is beneficial for effective control. Small populations can be controlled manually since roots are shallow and plants can be pulled up fairly easy. This would have limited impact to the surrounding habitat. For slightly larger areas of invasion mechanical methods can be used, either mowing or weed whacking. But seasonal timing is very important as well, any control method should be applied or conducted in late August to early September when plants are late in flowering stage but have not started to set seed. If plants are removed too early new seeds will germinate quickly and can mature rapidly.
Chemical control: For more extensive invasions chemical means are necessary because manual methods would be too overwhelming and time consuming. Chemical treatment should also be applied late in the season and can be more effective if mowed prior to application. The herbicide Imazameth is the best option for controlling stilt grass because it allows the native broad leaved plants to revegetate the treated area. Treatment with Imazameth requires 6 ounces per acre. Sethoxydin applied at a 1.5% solution mixed with water and a 1% nonphytotoxic vegetable-based oil can also provide excellent control. Sethydoxin also kills grasses without causing damage to the dicot species. Glyphosate can also be used, but would be more ideal in monotypic stands because it results in death of all plants. This may actually contribute to stilt grass becoming dominant, if monitoring and treatment is not applied the following year. There are also glyphosate formula's designed for wetland areas (Rodeo). Glyphosate should be applied at a 2% solution with water and a 0.5% surfacant. All herbicides should be sprayed to thoroughly wet the surface of the plants, but should not be sprayed to the point of run-off. Herbicides should not be applied when rain is expected within two hours. Ambient air temperature should also be above 65 degrees Fahrenheit for better transport of herbicide to the root system.
No biological controls have been found effective. Grazing is not an option either; cattle, deer, and even goats avoid feeding on it.
Flooding has been found to work, but needs to be fairly constant over a three month period for mature plants and ten weeks for seeds. Seeds have been shown to germinate under water, but plants cannot survive. If water is removed too soon more seeds will germinate. This is not a realistic method over large areas and would be best applied to monoculture stands due to intense ecological effects and negative impacts on other species.
Prescribed burns in the Spring are ineffective, because of large seed banks. Thus far, fall burns have not proven to be very effective either.
No matter which control method is used, it is necessary to follow up and monitor in successive years due to the large seed bank. Seeds remain viable in the soil for up to five years.
One of the links on that first page took you to a NC site where they had this option.
In my seng beds I think I would elect to control it by pulling it up. In areas near my seng beds I might consider some type of chemical control if that is necessary to keep it from getting back into my seng planting sights.
Preen has a fertilizer additive which dependent upon your growing method may not be desirable. As far as a pre-emergent hurting your ginseng, it will not. I use it repeatively in my landscaping business, it's chemicals just retards germination of any type of seed. Many different forms are available.
Over the past two years, this packing-grass has quickly over-run many of the fields and disturbed areas on our land. I have never encountered anything like this. I can only imagine what it will look like in a few more years. The good thing about this grass is that it is easily pulled out (shallow roots and long stems), however, I found that this does not completely eradicate the patch and it must be pulled multiple times.
I am going to post some pictures after this weather dries up. It is not looking good. Three of my prime ginseng cultivation areas are compromised, and for the time being it is only getting worse.