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Atrazine Establishment Plan for Diversity

Following an establishment plan

To maximize your investment in seed, follow the establishment plan to get the best chance of success. These timelines are guidelines. Weather and individual situations can change the process and the dates mentioned are only recommendations.

During establishment and for the life of a native planting, always consider the movement of seed with vehicles and equipment. We recommend you blow down or wash off equipment and vehicles before entering the field, especially if the equipment/vehicle was recently used in a field ripe with seed of a species you do not want in your native planting (e.g. fescue, sericea, Johnsongrass).

Choose the best timeline

If you’re not sure this is the right establishment plan for your situation, use our Planting Timeline Selector or read the Establishment Plans Overview.

Considerations when establishing with Atrazine

Both the University of Missouri Extension and Natural Resources Conservation Service (NRCS) have outlined establishment plans for Eastern Gama Grass using Atrazine (see note below). This guide for establishing diversity is an adaptation of these plans. Be aware: the disadvantage to using Atrazine is that the planting will be dominated by the native warm season grasses.

These guidelines are for fescue/clover pastures. If the pasture contains Bermudagrass, Johnson Grass, Sericea Lespedeza, Caucasian Bluestem, Crown Vetch, an overabundance of Broomsedge or other problematic species, the guidelines may need to be adjusted. If the field was previously planted to corn or sorghum for many years, see the Establishment Timeline for Crop Fields.

The timeline below details a process to kill the existing vegetation, but an alternative is to grow glyphosate-resistant crops for two consecutive years before planting natives. See the notes below for more information on cropping to establish natives.

Kill existing vegetation

before starting establishment
It’s crucial to remove unwanted trees and other unwanted obstructions from within the field and its edges before staring establishment plan. Fewer obstacles in the field (e.g. unwanted buildings, equipment, trees, brush, fence, etc.) make it easier to get equipment around the field and therefore get a better kill without as much hand work. A better kill will decrease the chance of reinvasion of undesirable plants from the edges and spray misses. While this step is optional, it is a good idea to take a look at the site with this in mind before starting the other actions in this timeline.
early August, year 1
Before fall rains, graze, mow, or hay the area so that it will be actively growing and herbicide can make good contact with the regrowth of all plants.
September 1-15, year 1
Fescue should be sprayed when actively growing. If the fall rains have not come, delay the spraying until fescue is actively growing. If fescue is really the only weed of concern, the field can even be sprayed up through early November. Follow up on any misses and pay special attention to fence lines, field borders, areas under trees, creek banks, and other hard to get to areas.

Plant native seeds

around April, year 2

Plant only the Atrazine-tolerant native warm season grasses. At the same time plant a nurse crop, usually corn. This should be a thin planting, and the nurse crop can be drilled in while the native warm season grasses are broadcasted. Or the nurse crop can be drilled in perpendicularly to that of the native warm season grass drilling.

Anytime within 3-5 days before or after planting, spray the field with glyphosate (which will kill green, actively growing plants) and apply two pounds per acre of Atrazine (which will give residual control of many annual weeds). Atrazine requires a rainfall event of half an inch after spraying to have a successful kill.

around early November, year 2
After hard freeze, but before it gets too cold, apply glyphosate one last time to the field. This is one last attempt to kill fescue and other weed seedlings.
winter
The remaining seed (i.e. forbs, cool season grasses, and other native warm season grass species) can be planted in winter between November 15 and February 15.

Notes on using herbicides

Always read and follow label directions of an herbicide! The labels are not only helpful in knowing how to be safe, but they also provide great information about how the herbicide is most effective and how to keep the soil and environment healthy.

Also, make sure to understand the legalities of Atrazine as it is a restricted-use herbicide.

Notes on cropping an area

Another alternative to the “Kill existing vegetation” section of the establishment plan above is to grow glyphosate-resistant crops for two consecutive years before jumping in with the “Plant native seeds” section. Other herbicide/crop combinations may also be used, but it is important to ensure the herbicides do not have a carryover problem in the soil that will impact the native seedlings.

Identify the plants in the field so that the proper herbicide(s) may be used. During the two years of cropping before establishing natives, make sure that weed seeds do not fall on the ground, and also make sure that the perennial plants have been killed.

Crops may be harvested by any means that do not introduce weed seeds to the field, such as combine, cutting for silage, or grazing.

When converting crop fields, usually field borders, fence lines, grassed waterways, etc. are not killed out and planted to crop, but it is important to make sure these areas also undergo cropping for two years or the timeline outlined above is followed on these areas. If this is not done, seeds from these areas pollute and invade the native planting.

Sometimes long-term crop fields do not establish well, possibly because the soil biology is unhealthy. If you feel this is the case with your field, consider cover cropping and other techniques to boost soil health before planting natives.

Note on Atrazine studies

This guide for establishing diversity is an adaptation of others’ plans for planting Eastern Gamagrass with Atrazine. One such establishment plan is the recent MU Extension guide by Kallenbach and Roberts, called Eastern Gamagrass. It explains a couple methods for using Atrazine in Eastern Gamagrass establishment. Because Eastern Gamagrass is not on the label for Atrazine, the herbicide must either be used in prior production of a crop that is on the label or planted with a crop that is on the label.

Kallenbach and Roberts describe that Atrazine can be used at full rates in the production of corn or sorghum for several years prior to planting Eastern Gamagrass; this should provide adequate carry-over for weed control during establishment. They also outline a plan to use a nurse crop, such as a thin seeding of grain sorghum or a sorghum-Sudan grass hybrid and apply Atrazine at one pound per acre to the nurse crop. The Eastern Gamagrass is seeded with the nurse crop. The nurse crop can later be harvested for hay.

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