Weed control 101
I was scrolling through my Archives of past email tips (which by the way go back to 2002) thinking I had done an all-inclusive weed-control tip sheet that I could refer everyone back to. But as it turns out, none of the titles of each of those tip sheets indicated that. So, I'm sure some people just scrolled right by them. This is why I've made this week's email tip a compilation of everything I have written in the past about weed control over the years. Or, WEED CONTROL 101.
I'm also pretty sure I noted on the air this past weekend, that while many people are itching to get going in the landscapes, the calendar is holding us back just a bit. However, there are many turf grass control products we can put down over the next several weeks, to at least give us something to do if we are "chompin' at that proverbial bit."
You can put down the Early Spring Green Up 15-5-10 (read more about later and at this link)
You can put down the February Pre-Emergent Herbicide (see schedule)
You can spray broadleaf weeds with Post-Emergent Herbicides. (below)
You can core aerate (March & April are still better, but it won't hurt now)
You can put out mulch Randy sez: You can never have enough mulch!
You can prune your trees and your crapes (just don't over-do it)
But before we start calling up any of that old information from those archived tip sheets, I want to make some very basic points and list a few products that work great to knock back the weeds right now.
First, if you have a preponderance of weeds, it's likely you have very unhealthy soil and/or you're not following THE SCHEDULE (see above), which promotes the importance of pre-emergent herbicides. Also lumped into the first point, is how we can blame a larger-assortment-than-normal weed crop this year on Hurricane Ike. Secondly, the healthier the yard, the better natural defense it is against weeds with or without the pre-emergence. You get to a healthier yard by 1. Following the Schedule, 2. Mowing at the appropriate height 3. Making sure you keep up good irrigation/watering practices. Thirdly, most of the weeds that have cropped up now can be hit with a broadleaf weed killer. The grassy weed known as Poa Annua can honestly be left alone, and will die off in 80 degree temperatures or it can be yanked out quite easily. The grassy weeds that are hard to pull up are the ones that rear their head in late spring and early summer such as crabgrass, dallisgrass and goosegrass. Yet, they can be prevented so easily with that February/March pre-emergent application as noted earlier and listed in My Fertilization Schedule.
The products that can be used right now are what we refer to as post-emergent herbicides and more specifically the "cool season herbicides." And while the temperatures are still 45-75 degrees these are the ones that can and should be used: Fertilome Weed Free Zone & Bonide Weed Beater Ultra. There are a couple of new granular products that are considered an environmentally safe replacement for the Atrizine-based Weed & Feeds and they can be used at any time of the year. (More on all that in an older tip sheet). Fertilome's is called Dollarweed Control Plus and GreenLight's is a granular version of Wipe Out. Since these products are so new to the market, there are no google images of them, so you'll just have to remember the names, or print out this tip sheet and take it with you to your garden center of choice.
Personally, I've always recommended the liquid versions of broadleaf weed control, because the granular weed-and-feeds with atrizine are so damaging to groundwater supplies and roots of trees and shrubs in the area. Plus, you can spot treat with the liquids. However, I am impressed by the early research of the aforementioned Atrizine-Replacements. The active ingredient of the Fertilome Dollarweed Control Plus is known as Penoxsulam. Needless to say the products are so new that we have scant empirical data to back up the early claims. Yet, I'm confident that I will be recommending such products more and more. Having said that, I can see where I will only recommend them to people with a huge weed problem. With a few weeds here and there it is still better to spot-treat from an environmental pressure.
If you wait to control such broadleaf weeds when the daytime highs start creeping into the 80s again, then stick with the three most well-known broadleaf weed controls on the market – GreenLight Wipe Out, Bonide Weed Beater for Southern Lawns & Fertilome Weed Out. The previously-mentioned cool season herbicides become ineffective and stressful to grasses, once the high temperatures are consistently in the 80s. As always, with any liquid weed control, be it the cool season herbicides or these three, please use a surfactant. If you are unfamiliar with my reasons to use a surfactant, please read this tip sheet from our webpage.
MAJOR WARNING: You will see many other supposed weed killers and broadleaf weed killers at several mass merchandisers and box stores. In many cases, if you'll read the label, they are not formulated for southern turfgrasses like St. Augustine. That's why I recommend only those listed earlier in this email tip.
I've tried to make it pretty easy in breaking down the difference between grassy weeds and broadleaf weeds, in that most of the obnoxious weeds that are up right now (such as Dollarweed, Clover, Dandelion, Thistle, Chickweed, Henbit, Wild Geranium, Nettle etc. etc. etc.) are all broadleaf weeds. The only annoying grassy weed that's up right now is Poa Annua (wild bluegrass), and that doesn't look half bad as long as it stays mowed and it will burn off with the heat, so I don't pay it much attention. I just do a better job of preventing it with the November pre-emergent herbicide this coming fall. Even if trying to make it simple on the surface for you, some of you still may want to know what exactly what you are dealing with. Well here's a handy website for weed identification.
Now, here is sort of a compilation of the older tip sheets I've written over the years, and you'll understand that while there's lots about weed control in there, you'll also see why they weren't labeled as WEED CONTROL 101 type tip sheets.
EARLY GREEN UP TRICKS OF THE TRADE
The best kept secret in lawn fertilization, one that was even kept from me up until two years ago, is the use of a basic 3-1-2 ratio fertilizer in late February/early March. You may recognize the ratio from the GardenLine fertilization schedule mentioned earlier. Only this 3-1-2 is a basic, immediate release fertilization. And the best fertilizer I've found for this very purpose is a 15-5-10. But remember it should not have the words slow-release or controlled-release on the bag. The pratfall that most everyone encounters after being lulled into a false sense of security from the early green up, is forgetting to follow the basic fertilization schedule at the first of April. Another hurdle is to make sure that there are no freezes on the horizon. But all is not lost even if you miss the basic fertilization by 2-3 weeks. Just get busy, and try to get back on schedule.
As any diehard LemmonHead would know, I don't' recommend weed-and-feed fertilizers at all, because of the Atrizine compound found in most. However, I couldn't help but get a giggle out of my "tacit approval" writing from nearly 7 years ago in this entry. And while all of it is still very true, the good news is that there is a granular weed control (but not a fertilizer per se) that I do approve of from Fertilome called Dollarweed Control Plus. So, after you read this 7 year old entry, you can use the new Fertilome product in place of any weed-and-feed such as Scotts Bonus S
WEED - AND - FEED
Touchy subject for me, but there is a limited window of opportunity that I recommend using a weed-and-feed. But be forewarned, I've never been a big fan of weed-and-feeds because most carry a very caustic chemical known as Atrizine. And, if misused or over-applied, Atrizine is notorious for moving very quickly through soil and eventually contaminating ground water. Beyond that, the other main reason I have trouble recommending it is because of the way it burns roots of trees and shrubs. Just read the bag... even the weed-and-feeds warn against getting it near the drip line of trees and shrubs. But I do realize that many people need to solve the problem of winter weeds before they get busy with the basic fertilization schedule. So, here is your one and only opportunity. But in order to use a weed-and-feed, especially one with the Atrizine herbicide, take have to take this annual pledge with me: I (INSERT NAME HERE) DO SOLEMLY PLEDGE TO USE A WEED- AND-FEED FERTILIZER ONLY ONCE IN A YEAR AND I FURTHER PLEDGE TO MAKE SURE THAT I FOLLOW APPLICATION INSTRUCTIONS EXPLICITALLY, SO AS NOT TO OVER USE OR OVER- APPLY BASED ON THE THREAT THAT SOME WEED-AND-FEEDS POSE TO OUR GROUNDWATER SUPPLIES AND TENDER ROOTS OF TREES SHRUBS. WITH JUSTICE AND GARDENLINE FOR ALL!!!
Now back to basics on Weed Control, and it boils down to understanding the differences between PRE-EMERGENT and POST EMERGENT herbicides.
When ever these subjects come up, I'm never sure whether to talk first about the "weeds to come" or the weeds that may "already be up" in the lawn. Since most of the weeds that are up now will burn away in the heat of a Texas summer, let's focus first on keeping late spring and summer weeds from being a problem. This too is done during the end of February through the first of March with Pre- Emergent Herbicides. More specifically we are looking for the pre- emergent herbicides to control the grassy weeds that are such a problem from May through July - weeds like Crabgrass, Goosegrass, Dallisgrass and Johnsongrass.
The only truly effective way to control these weeds is to prevent them from being a problem. The beauty of the pre-emergent herbicides, if you think about it, means that if you do the pre-emergent right, you'll never need to use a weed-and-feed like we talked about earlier. But it is critical that these pre-emergent applications are put out before the end of March. The best pre-emergent herbicides for February application are Barricade and Dimension. I use to recommend another two-in-one by the name of Pendulum, (active ingredient Pendemethlin) but I haven't seen it at a garden center in 5 years. Preen is another brand-name pre-emergent that people can find at big box stores much easier that the Barricade or Dimension products that are usually from the Nitro Phos, Fertilome companies that I recommend week in and week out. And those are found at smaller independent nurseries and garden centers in Houston. There are other pre-emergents by the names of Betasan, Treflan, Surflan. Green Light makes two three pre-emergent herbicides for this purpose. One is known as First Down and the other is Amaze. The third bag from Green Light simply says Betasan.
Usually, if you have a bunch of weeds already up, they are what we know as the winter germinating weeds and they could have been prevented with the use of two pre-emergent herbicides back in November. Nevertheless, if that didn't take place or if for any other number of reasons you have clover and poa annua or chickweed, or henbit and other groups of nefarious weeds out and about, then let's knock them back with a post-emergent herbicide. Most post-emergent herbicides kill only broadleaf weeds. So, if you're problem is mostly the thin seed-head heavy poa annua (that often looks like rye grass gone bad) don't worry heat will take care of it. Most post-emergent herbicides are also of the liquid variety. You can either use a concentrate in your own pump-up sprayer or a dial-in hose-end sprayer. But the best news in recent years is the technological advancement of the ready-to-use sprays you simply attach to the end of a water hose.
As of 1999 the best names for post-emergent herbicides were Green Light Wipe Out; Fertilome's Weed Out and more recently Bonide's Weed Beater for Southern Lawns. The Green Light and Bonide products are two that I know come in a ready-to-use form that attach to the hose. In all cases, these products must be used according to the instructions. And here's your final "best kept secret" with regards to the broadleaf weed killers... My two favorites are Spreader/Sticker from Hi Yield and Bonide's Turbo. Also, make note, that some of the Ready-To-Use sprays might have a "surfactant" built in. Just read the label. Finally, I don't care how bad you think the weed problem is, if you try to double the dosage of any of the products I just recommended, you will almost assuredly kill your grass.
Until next issue, here's to Great Gardening from the GardenLine, heard exclusively, 6-10 a.m. Saturdays and 7-10 a.m. Sundays, only on NewsRadio 740 KTRH.
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