Proactive Weed Control

Horticulture Hotline 02/06/17

By Bill Lamson-Scribner

The soil temperature indicates that it is just about time to apply preemergent products to your beds and turf. Valentine’s Day and the running of the Daytona 500 are just around the corner. The time to apply the magical weed preventer is coming up fast, and this year, since our winter has been pretty mild and the ground has been insulated with moisture,

the time might come a little early.

Depending on which Phd doctor you believe, crabgrass germinates when the soil temperature (3 inches deep) stays above 55 degrees (some people say 57 degrees), for 3 straight days provided adequate moisture in the soil. Now some doctors say remains 57 degrees or above for 24 hours at a depth of 3 inches with adequate moisture.  If you are not in to monitoring the soil temperature, Valentine’s Day or the running of the Daytona 500 should work for you. Spreading a preemergent product now could save hours of spot spraying later.

The turf areas as well as the landscape bed areas will greatly benefit from the use of preemerge products. Not only will the yard look better, but your plants will not have to compete with the weeds for sun, nutrients, and water. If you are controlling weeds with preemergent products, there are less weeds there for you to spray or pull, saving you time. There is also less stress on you trying to find time to control the weeds in your yard later once the weeds have emerged. Control them now with a preemergent control product!

For those new readers of the Horticulture Hotline, preemergent control products kill weeds as they germinate.  The weeds never come up and you never have to worry about them.  Crabgrass, goosegrass, barnyardgrass, crowfootgrass, dallisgrass (seedling), foxtail, annual bluegrass, smutgrass, barley, kikuyugrass, wild oats, bittercress, carpetweed, chickweed, Carolina geranium, henbit, knotweed, lespedeza, marestail, black medic, mustard, oxalis, pineappleweed, pigweed, redroot, parsley-piert, purslane, rocket, shephardspurse, speedwell, spurge, and woodsorrel are examples of weeds controlled by preemergent products.  Small seeded annual weeds are controlled by preemergent products.

Read the label of the specific product that you are using to get an exact list of weeds that the manufacturer has tested and shown to control. Preemergent products applied now do not control winter annual weeds that are already up like annual blue grass. To control annual bluegrass, you would have used a preemergent in August and again in October (this could vary with products and rates).

Clover, Florida Betony, Nutsedge and Dollar weed are not controlled by preemergent control products.  These are perennial weeds. Weed Free Zone is a liquid that will do a good job on controlling many of your broadleaf weeds. The Nutsedge will require a different product and is most likely not visible right now.  It is important to control these weeds now before they go into their reproductive stage.  A weed in its reproductive stage is harder to control than a weed in its vegetative stage. By controlling the weed now you avoid having to deal with more weed seeds next year.

It is very noticeable when you ride through the Lowcountry which homeowners and which businesses used preemergent products last fall at the correct time. One business or home lawn will be nice and brown and dormant without a spec of green in sight. Right next to it will be brown turf mixed with green weeds. Again, it is very important to control those weeds now before they begin to flower.

Always read, understand and follow product label. The product label is a Federal Law.

Weeds, Weeds, and More Weeds

Horticulture Hotline 1/30/17

  Bill Lamson-Scribner

Winter weeds seem to be in rare form this year. Chickweed is what I’m seeing most as a broadleaf weed and that annoying annual bluegrass is maintaining its place at the top of the grassy weeds division. Right now is the time to kill these weeds before they produce seed for next year’s crop.

With the warm winter, we have had, you will probably get your best results if you mow your lawn (and weeds), wait 2 or 3 days, apply a weed killer, then wait a week or two before you mow again. You want the weeds to be actively growing, so they absorb the control product. Then you want to give the weed time to translocate the active ingredient before you mow it again.

Henbit, clover, Florida Betony, lawn burweed (definitely want to kill before the burr is sticking your feet – Gamecocks call it Spurweed)), hairy bittercress, Carolina geranium, thistles, dandelion, and the list goes on… are some of the weeds being a pain in the grass.

Weeds are much easier to kill now while they are actively growing in the vegetative part of their life cycle then when they are in the reproductive part of their life cycle (usually March  / April here depending on the weather – this year seems a little early). Kill the weeds now! The PHD doctors have figure that one annual bluegrass plant produces 2500 viable seeds. Think about what happens if your weeds are not maintained for a year or two. In one year that is 6,250,000 weed seeds, after that my calculator errors out!

Your grass doesn’t usually like to be treated with herbicides while coming out of dormancy (in transition) either, so it is much better to control the weeds now while the grass is dormant.

With preemergent time for summer annuals coming up so quickly, I plan to treat for the winter weeds that are growing now and put out a preemerge at the same time. By putting out the pre and post emerge, I will prevent any sneaky late germinating winter weeds that will try to pop up and re-seed themselves this spring.

At Possum’s (and many other local stores) we have many different herbicides to meet your needs to kill your weeds!

There is a Fungus Among Us

Horticulture Hotline 01/23/2017

By Bill Lamson-Scribner

The basically warm, high humidity winter has finally made fungus explode throughout the Lowcountry. I don’t like to cause panic. We have only sent out one email alert in 14 years from our stores. (If you would like to get on our email list, stop by any of our 3 Possum Landscape and Pest Control Supply stores to sign up.) The rains of 2015 and 2016 (Matthew) really spread the fungus to new levels. These new areas of infection are showing up now with the perfect environmental conditions and are likely to show up again this spring. Be ready. Fungicides work like the flu shot – they are best to be used preventatively before you have the disease. Unlike the flu shot, if you don’t get it out in time, there are curative rates you can use.

Large Patch or Brown Patch fungus loves these weather conditions. Temperatures at night in the high 50’s to low 60’s and moisture make conditions real favorable for Large Patch or Brown Patch fungus. We have had plenty of these conditions making the fungus environment perfect for the spread of this disease. Fog, rain, no sun (Saturday I heard someone blame the weather on Trump) and the perfect temperatures has caused disease on areas I have never seen disease before. With these weather conditions, you see those round, yellow areas of disease. Or sometimes the whole yard is covered in disease. Walk through your neighborhood, you will see what I mean.

Since it is very difficult to control night time temperatures and humidity, you can put your efforts into doing other cultural things to help minimize the disease. Large Patch or Brown Patch fungus likes wet, heavy thatch, improper nutrition, and/or compacted soils.   Culturally you need to manage your irrigation system, raise any low areas, and correct drainage problems.  Reducing thatch (now or when the grass is growing - BGK 7500, when grass is growing - aeration or dethatching), maintaining proper fertility levels via soil testing, and aerating to alleviate compaction, will also help control Large Patch or Brown Patch fungus.

Certain organic products have shown to increase microorganisms in the soil that compete with plant pathogenic fungus in the soil. At Possum’s we get good feedback from Nature’s Blend, SeaHume, Crab Shell, Corn Gluten, Cotton Burr Compost, and some of the Roots products. These products are not fungicides; however, people that use them report back to us that they notice less fungus in the yards that they apply these products. Coincidence or real science? I’m thinking real science because I have noticed it in my yard too. Try some of these products in areas that you know you get the disease, and see how it works for you.

Since the grass is semi-dormant, a systemic control product like T-Methyl or Fame might be a good idea to get you through the next month or so as long as conditions are favorable for the disease. Be careful because some of the fungicides in the SI or DMI class (Bayleton) of chemistry slow down the growth of the grass making the grass more susceptible to fungus. Actively growing grass will recover faster from disease.

Being a soil borne disease, you know that it will reoccur in the same areas year after year.  If the base of a leaf blade with Large Patch is moved from one part of the yard to another (lawn mower – not real likely if you have sharp blades), this can begin a new infection area; however, these are not spores flying through the air.  As a soil borne fungus, if you map the areas that you have the disease, you can concentrate your control efforts (dollars) into a smaller area, putting less control products into the environment.  If your yard is 5,000 sq ft usually you might have a few infected areas which might total approx. 500 ft.  Instead of buying control products to treat 5,000 sq ft, you can concentrate your efforts into the 500 ft (i.e. 10% of your total yard).  If Large Patch was an air borne fungus with spores, you would have had to treat the entire yard because air borne fungus spreads a lot quicker than soil borne fungus.

Always read, understand and follow product label. The product label is a Federal Law.