We continue to experience really cold temperatures in the Tulsa area this winter. I've written about how extreme cold temperatures could affect bermudagrass turf in a negative way. Winterkill is always something turfgrass managers worry about when temperatures hover around zero for very long. We shall see later this spring how our turf has held up. And, we still have some winter to go before spring does get here. Some of the most susceptible times for bermudagrass is in late March and early April, when even temps in the mid-20's can damage grass that has already started to green-up.
But what about pre and post-emergent weed-control
? Does this very cold weather affect it now? Pre-emmergents are watered into the soil where they are activated and stop weed seeds from germinating for many months. Cold weather does not affect that at all, with the product staying in the very top layer of soil and waiting for warmer soil temperatures along with seed germination. The pre-emergent must be applied and into the soil well before any weeds begin to germinate, so these products need to be applied often when it's cold in early spring. They really don't break down much until the soil temperatures rise and the soil stays damp.
Any existing winter annual weeds are still fairly small with the cold temperatures. Generally, they are much easier to control when small. In fact, that's one big reason we treat those the previous fall for our existing customers, so they do not have hardly any weeds now that need to be controlled. New customers however often have alot of weeds, so they need to be treated with post-emergent herbicides. At LawnAmerica, we use two products on bermudagrass and zoysiagrass, Trimec and Atrazine. The Trimec will kill broadleaf weeds, but very slowly when it is this cold. The Atrazine is soil absorbed, so provides us with even better control on broadleaf weeds and grassy weeds such as Poa Annua. Again though, it works very slow during cold weather. As temperatures rise, the weeds will die out faster, but they will also be larger then and harder to control at the same time.
The cold weather mainly affects our guys who are applying the products……brrrrrrrr! And, homeowners need to water in the product within a few days, even though it may be cold. However, it seems latelly that it could be freezing cold one day, and a few days later you can be working outside in your shorts as I did Sunday afternoon. Spring will be here soon enough, and we can't wait here at LawnAmerica!
You know it's finally turning springtime in Tulsa, as some lawns and turf areas are turning blue or light green. It's not because the bermudagrass is greening up or changing colors, but rather a dye or paint that some lawncare companies in Tulsa use as a marker. There is no agronomic benefit to the blue or green color, it just shows the applicator where they have been, so as not to over or under-apply weed-control products. That's fine for someone who may be inexperienced, or not trained very well, since they can just be told to go out and paint the lawn blue. But in this particular case, as you can see, the appicator missed areas, and overapplied other areas, leading to inconsistent pre-emergent weed-control.
At LawnAmerica, we don't use the blue dye, as our Technicians are well-trained, experienced, and know what they are doing. As long as the proper techniques are used in spraying, there is no need for the dye. We'd rather invest our money into products that actually help control weeds, with quality pre-emergent herbicides and post-emergent weed-controls. Plus, the dyes are messy, with homeowners tracking the dye into the home, blue dogs, blue fences and buildings, etc.
The blue dyes will eventually fade out with time. The important part of the mix are the products in it to help control weeds. We use Barricade pre-emergent, the best on the market, applied at a strong rate. It does need to be watered into the soil within a few days in order to activate the product. It's very dry in Tulsa, so your lawn will benefit from irriation also. Once in the soil, it stays there for up to 7-8 months, before degridation by soil microbes. For our 6 and 7-step customers, we apply another booster application of Barricade in about 3 months, along with nutgrass and broadleaf weed-control.
Even the best pre-emergent products, if not applied correctly and at the proper time, will not be effective in providing great weed-control. But you don't have to have a blue lawn to get there….you just need the right company and the best technicians applying the products.
The 2014 Tulsa HBA Home & Garden Show starts next Thursday at the fairgrounds. This will be my 25th Tulsa homeshow to work at, along with many other smaller ones. This one is a great show, with most of the professionals dealing with just about anything relating to caring for your home on display. We'll be there with Big Jake, our 9' LawnAmerica guy, and our new puppet show, featuring Robbie as he does battle with weeds in the lawn. Stop by and say Hi this next weekend and we'll give you a gift if you are a current customer. If not, you can sign up for a free estimate, and have a chance to win one of 5 family vactions valued at $2,000 in our Spring Vacation Giveaway.
Today is the last day of February, and while we are recieving a light rain now, it's been the driest first two months of the year ever in Tulsa. We've been encouraging our customers to water their lawns and landscapes, as even during the winter months soil moisture is important for the health of turf, trees, and shrubs. Young and newly planted shrubs and trees especially since their root systems are not developed, need good irrigation.
Winterkill of bermudagrass will probably be an issue, if not a big problem this spring. Keeping your soil moist so that the crown and root system of your turf is not surrounded by dry soil will help prevent winterkill. A dry soil becomes much colder than one which is moist, as water is a heat moderator. Dry land heats up, and cools down, faster than water. Rembember learning that in your old science class? At least I taught it back in the day I was a science teacher. If there is any good news with the cold start to early spring, it's that there is still plenty of time to apply a pre-emergent herbicide in order to stop crabgrass from germinating. With the cold soil temperatures, it will likely be early to mid-April before we see the first flush of germination.
The winter of 2013/2014 in Oklahoma is turning out to be one of the coldest in recent memory. And now comes the snow, which makes our job in applying early spring pre-emergent a lot tougher. At least crabgrass will not be germinating anytime soon in Tulsa, as the soil temperatures are way down there.
But that is also becoming a concern. Winterkill of bermudagrass is also something we’ve not seen a lot of in ulsa over the past 20 years or so. Sure, we’ve had some minor and spotty winterkill during a few winters, but nothing major like the winter and spring of 1991. About 50% of the bermudagrass in Tulsa actually died that winter, leaving homeowners and turfgrass managers to patiently wait for the turf to recover and re-sod in many cases. Bermudagrass is a warm-season grass, and we are in the transition zone here in Tulsa, on the northern edge of where bermudagrass can grow. So when extreme winter weather happens, turf will be affected.
While we’ve not experienced extreme sub-zero cold, which will damage bermudagrass, the longevity of these cold temperatures is what concerns me. This week looks to be below freezing all week. We’ve had very few of those nice, warm January days which heat up the soil. So unless we have a shift in our weather patterns, I’m betting on at least some damage to turf in Tulsa and Northeast Oklahoma.
The snow cover we have now will help some, as that insulates the crown and root system of the turf somewhat. The snow will also help provide some much needed soil moisture, if it ever melts that is! It is very dry, so later in February, I recommend watering your lawn and landscape. I know I have kicked on my irrigation system manually this winter about four times now. This will help prevent possible damage to turf and landscape plants.
Crape Myrtles are one plant susceptible to cold winter temperatures. They also can be pruned in the late winter, as they are dormant. I would caution that however, as many of these plants are over-pruned in Tulsa. They can be leaf un-pruned, and allowed to grow 20’ high if you like. If the area they are growing in allows that, this would be my recommendation. Other trees and dormant shrubs can be pruned now in winter, by taking out dead limbs and shaping the tree to allow for future growth this spring and summer.
Many homeowners do not realize that even during the winter, a lawn and landscape stills needs good soil moisture. So far in 2014, we've not had much rain or snow at all, with nothing but dry, cold weather in the forecast. It's causing wildfires to pop up in Oklahoma. And the dry weather could pose a problem for trees and shrubs unless they are irrigated some soon.
While turfgrass is not experiencing much topgrowth during winter, and bermudagass is brown and dormant, the root system of the plant is still alive and growing somewhat. Fescue is green, but when it is cold and dry, turns off color somewhat to a brownish green. One big concern is that winterkill of bermudagrass can be much more severe when turf is grown under dry soil conditions. Some soil moisture will moderate the cold soil temperatures, and prevent winter damage in many situations, compared to turf grown in dry soils. It's been a very cold winter, especially compared to previous winters in Tulsa. And it's not over yet, so we could still experience some severe arctic blasts before springtime.
Wait for a warm day to irrigate!Just kick you irrigation system on manually and let it run for 20 minutes or so per cycle. It won't take much to get some moisture into the soil. If you don't have an automatic system, pick one of those nice days in between the cold ones, and set your hose and sprinkler out to deliver about 1/4" of moisture at least, which is not much really. Trees and shrubs, especially ones planted last year, will need some soil moisture in and around the root system.
We have started our R1 Weed-Control Treatment at LawnAmerica, so the pre-emergent herbicide needs to be watered into the soil within a few days also. So watering during the winter is sometimes needed in Oklahoma. I know it's a hassle, but if you've ever experinced winterkill of bermudagrass, it's not pretty. A little prevention now could prevent major problems on down the road this spring.