June 8, 2013
“Spwingtime has a few more wacky wascals” as ol Elmer might say. We spoke before about insects that appear as we approach 60 degree Fahrenheit. This is also the temperature to trigger weed growth.
Let’s talk about lawns first. Nationally, lawns are broken down into warm season and cool season grasses. Warm season lawns are Bermuda, Zoyzia, and St. Augustine grasses, normally found below the Mason-Dixon Line. We will assume that most reading this article in Southern Ohio will have cool season lawns, typically Bluegrass, perennial rye, tall fescue, and/or red fescue. A good way to look at lawn maintenance is that it’s a sequential, ongoing program. It’s a pragmatic thing. Each application is done with the next ones in mind.
There are many brand names and gimmicks on today’s lawn care market, but here’s some basic information. Lawn treatments are either pre-emergent or post-emergent. “Pre-emergent” is a type of chemical that goes on early and doesn’t allow the weed seed to germinate. “Post-emergent chemicals are applied after the weed is up and growing. They are “contact” chemicals, meant to be absorbed into the leaf and kill the weed. They are usually a “growth regulator.” This means that the chemical either causes the plant to not perform photosynthesis stunt and die, or to “outgrow” itself. You will notice that when weeds are killed in lawns this way, they either “yellow-out” or get all twisted and contorted. Obviously, timing is very important when selecting pre-emergent or post-emergent applications.
These lawn treatment chemicals are in two other categories also – selective and non-selective. When treating a lawn, make sure that the chemical is selective and to be used on cool season grasses. This means that it’s going to “select” the weeds that it’s engineered to kill and not harm your bluegrass, rye, or fescue. Today’s chemical market is becoming more and more selective. Thirty years ago, when I first started treating lawns, you could only treat crabgrass with a pre-emergent. Think about that. It meant that you had to apply the treatment in February, before the seed germinated, or wait until next year. That gave you all of this season to look at crabgrass. We now have several post-emergent crabgrass treatment products. Another new breakthrough along this line would be a treatment and remedy for Johnson grass and another for nimblewill. We all know that the non-selective ROUNDUP will kill anything it’s sprayed on, so this was the previous remedy for Johnson grass or nimblewill. This was O.K. in driveways and fence lines, but not so good in lawns.
We place these lawn treatment products into yet two more categories – broadleaf or grassy weed types. The broadleaf control would include use on clover, thistle, dandelion, ground ivy, chickweed, plantain, henbit, etc. The grassy weeds would include crabgrass, goose grass, barnyard grass, nimblewill, etc. (Broadleaf is broad and grassy leaf is narrow).
This brings us to another factor in lawn application – the use of a surfactant or spreader sticker. This is another chemical used in the same tank mix to make the weed killer “stick” to the leaf and stem. This allows the sun to bake it into the plant.
We now also have treatments for sedge grass. This is a little more specific than just another grassy weed. There’s a saying, “Sedges have edges.” If you roll the sedge stem between your fingers, you will feel that it’s not round, but that it has edges.
One important thought on lawn and landscape maintenance would be that you get what you pay for. Homeowner products are for “Do-It-Yourself,” and they are “over-the-counter” products. The “restricted” chemicals are for licensed professionals and they work. They work because they are more specific, stronger, costly, and dangerous, and that’s why they’re not “on the shelf” for homeowner use. The manufacturer, USDA, EPA, and FDA don’t know you, your training, etc., but they do know about liability. DDT, chlorodane, dieldrin, diazanon, and many others are off the shelf and off the market, because they worked – too well. They were the gift that just kept on giving. When applied as per the label, they killed the target, but they kept on killing as they passed through the food chain. The eagle died that ate the coyote, that ate the mole, that ate the grub, that ate the chemical. These active ingredients had too much residual effect as they lingered too long and accumulated in predators and scavengers. They also “leached” out into streams and ponds for fish kill and into the ground water to contaminate drinking water.