James A. McAfee, Ph.D.
Extension Turfgrass Specialist
Texas AgriLife Extension Service
April 2, 2011
By now, most of the warm season turfgrasses have broken dormancy (greening up) and started to grow. The bermudagrass lawns are further along than the St. Augustinegrass and the centipedegrass lawns in spring green up. However, if no green up has occurred in the lawn or in sections of the lawn, then winter kill may be a problem. So far, it appears that the degree of winter kill/winter injury is a lot less than what was anticipated following a very cold winter period. Added to the low temperatures in the winter months are the extremely dry conditions across the state. Most areas of the state have been dry since last fall and if homeowners did not apply some supplemental irrigation to their landscape during the fall and winter months, then this could have added to the problems associated with low temperatures injury.
Providing adequate supplemental irrigation for spring green up is very important. If rainfall does not occur, then approximately 1.0 inch of supplemental irrigation water should be added to the lawn each week. While it is important to make sure adequate soil moisture is available for spring transition, it is also important to make sure the landscape is not over watered. Excess irrigation will create shallow rooted plants going into the hot, dry summer months and it can also encourage disease problems such as gray leaf spot in St. Augustinegrass. Also, with the dry conditions we need to make sure irrigation is being applied to the landscapes as efficiently as possible so there will be adequate water for the rest of the year.
Factors to help turfgrass through spring transition:
1. Provide adequate soil moisture for good spring growth. Again, approximately 1.0 inch per week if
adequate rainfall does not occur should meet the needs of the turfgrass plants.
2. While it is too late to scalp the turfgrass growing in the lawn, mowing the grass slightly lower than
normal and mowing it at least once per week will help force the grass to spread laterally and form a
dense stand of turfgrass. As temperatures start to warm up, mowing the turfgrass more than once per
week will help to force the grass to spread faster and form a dense lawn. Low, frequent mowing
along with fertilizer is the best way to force thin areas in the lawn to grow and thicken up in the
3. During the spring transition, use herbicides carefully, especially on the St. Augustinegrass and
Centipedegrass lawns. While bermudagrass and zoysiagrass can tolerate the spring applications
of most herbicides, St. Augustinegarss and Centipedegrass can be injured in some years. This is
especially true for lawns that might have already been injured by the hard freezes last winter. Once
the grass has totally greened up and is actively growing, then it should be safe to make a postemergent
herbicide application to the lawn.
4. Monitor the lawn for any insect or disease problems. If a pest problem occurs, then apply appropriate
controls to prevent the disease or insect from causing any damage. Fortunately, there are not a large
number of insect and disease problems at this time of the year on the warm season turfgrasses.
By now most people are aware that after December 31, 2010 organic arsenical herbicides such as MSMA, DSMA, etc. cannot be sold for use in residential lawns, commercial lawns, sports fields and right-of ways. However, if you purchased one of the organic arsenical herbicides prior to this deadline and still have some in inventory, then it can be used until you have depleted the inventory. The organic arsenicals herbicides can still be purchased for use on golf courses, sod farms and on cotton farms. For lawns and sports fields, the one weed that is going to be difficult to selectively control in bermudagrass and zoysiagrass is dallisgrass. At this stage, there really isn’t an effective herbicide for the selective control of dallisgrass.
With the losss of the organic arsenicals such as MSMA, it is going to be even more important that a spring preemergent herbicide application be applied for the control of summer annual grassy weeds such as crabgrass. In past, some people would use MSMA as a postemergent control for grassy weeds in large turf areas such as sports fields, golf fairways, etc. Cost of using the MSMA was generally less expensive than applying a preemergent herbicide. Now with the loss of MSMA, using a preemergent in the spring is going to probably be the best control for summer annual grassy weeds. Note, I still do not recommend a preemergent herbicide in spring for St. Augustinegrass and Centipedegrass lawns.
The herbicide Drive XLR 8 (quinclorac) does work pretty good as a postemergent on some grassy weeds such as crabgrass, barnyardgrass, broadleaf signalgrass and torpedograss. It is also affective on some of the broadleaf weeds commonly found in lawns. For the warm season turfgrasses, quinclorac is only labeled for use in bermudagrass, buffalograss and zoysiagrass. It can also be used in cool season turfgrasses such as Kentucky bluegrass, Tall Fescue and Perennial ryegrass. There are also several new herbicides on the market that contain quinclorac plus some of the hormone type herbicides which provide not only grassy weed control, but a wider range of broadleaf weeds. Also, there are several new products found in the garden/retail stores that contain quinclorac.
While the quinclorac will do a pretty good job of controlling crabgrass, timing is going to be very important. Quinclorac does a good job on young crabgrass seedlings and also works well on mature crabgrass plants. However, it is not as nearly effective for the intermediate stages of crabgrass growth.
Listed below are some of the new commercial brand herbicides sold for weed control in different turfgrass sites. Some of these new herbicides are also available in herbicides sold in the garden/retail stores. I have included several herbicide tables that contain the more commonly sold herbicides for use in home lawns.
1. Celsius (thiencarbazone, iodosulfuron, dicamba)
a. sold by Bayer Environmental Services
b. at this time not available in garden/retail stores
c. can be used in bermudagrass, St. Augustinegrass, Centipedegrass, zoysiagrass and buffalograss.
d. can be used to control broadleaf weeds in St. Augustinegrass and Centipedegrass lawns. There
are fewer and fewer herbicides labeled for broadleaf weed control in these lawns.
e. while it is primarily a postemergent broadleaf herbicide, some university researchers have observed
good control of young crabgrass seedlings. However, Bayer wants to see more research before
they place crabgrass on the label.
2. Specticle ( indaziflan)
a. also new product from Bayer Environmental Services
b. sold as a preemergent herbicide for use on bermudagrass, St. Augustinegrass, Buffalograss,
Centipedegrass, Bahiagrass and Zoysiagrass.
c. Applied at extremely low rates, 2.5 to 5.0 ounces per acre.
d. Excellent control of crabgrass, goosegrass and poa annua.
e. At this time is not available in the garden/retail market.
3. Lockup ( penoxsulam )
a. manufactured by Dow AgroSciences.
b. Dow is selling the active ingredient to different companies so they can make their own
formulations. Note, the Lockup is sold primarily as a granular product at this time.
c. Some companies are adding other postemergent herbicides such as 2,4-D and Dicamba to
help increase activity of the penoxsulam.
d. Lockup is being sold as herbicide only or some companies are blending it with a fertilizer and
selling it as a weed and feed.
e. Lockup is labeled for use on bermudagrass, Centipedegrass, zoysiagrass, Kentucky bluegrass,
perennial ryegrass and some fescues.
f. Has shown good activity on dollar weed, English daisy and white clover, but will also control
other broadleaf weeds.
4. Katana (flazasulfuron )
a. sold by PBI/Gordon, Inc. in the US
b. newest sulfonylurea herbicide
c. can be used in bermudagrass, centipedegrass and zoysiagrass.
d. excellent control of tallfescue
e. good ryegrass transition herbicide, works faster and in cooler weather than other sulfonylurea
f. works well on most of the sedges as well as some broadleaf weeds.
5. Solitare ( sulfentrazone + quinclorac )
a. manufactured by FMC
b. can be used on tall fescue, perennial ryegrass, bermudagrass, buffalograss, centipedegrass and
c. good activity on numerous broadleaf weeds and some of the sedges.
6. One Time ( quinclorac, mecroprop, dicamba )
a. manufactured by BASF
b. can be used safely on Kentucky bluegrass, buffalograss, tall fescue, ryegrass and zoysiagrass.
c. controls some of the grassy weeds such as crabgrass, foxtail and barnyard grass plus numerous
Following are several tables containing different herbicides sold in the garden/retail stores for purchase by homeowners. These are not complete lists of herbicides found in the garden/retail stores, but do contain some of the more commonly found products. Also, different stores carry different herbicide brands, so you may have to look at more than one store to found all of these herbicides.
It is always important to emphasize the importance of reading these herbicide labels before purchasing the herbicide and before applying the herbicide. These labels change and it is important to make sure it is still labeled for the type of turfgrass being grown in the lawn and that it is labeled for the weed that you are trying to control.
Table 1. Postemergent Herbicides for Control of Grassy Weeds in Home Lawns.
1. 2,4-D, Quinclorac, Bayer Advanced Lawn Weed & Crabgrass Killer
Dicamba Ferti-lome Weed Out With Q
2. Quinclorac, mecroprop_p, Ortho Weed B Gon Max Plus Crabgrass Killer
3. sulfentrazone, quinclorac Image Kills Crabrass
Remember, the herbicide quinclorac is only labeled for use in bermudagrass and zoysiagrass, so none of these products can be used in a St. Augustinegrass or Centipedegrass lawn.
Table 2. Postemergent Herbicides for Control of Broadleaf Weeds in Home Lawns.
1. 2,4-D 2,4-D Amine No. 4;
American 2,4-D Selective Weed Killer
2. 2,4-D, MCPP, dicamba Ace Spot Weed Killer
Green Light Wipe Out Broadleaf Weed Killer2
Ortho Weed-B-Gon Max
Specracide Weed Stop for Lawns
Hi-Yield Lawn Weed Killer
Ferti-lome Weed-Out Lawn Weed Killer
3. carfentrazone, 2,4-D, Ferti-lome Weed Free Zone
Mecroprop_p, dicamba Weed B Gon Max for Southern Lawns
4. 2,4-D, mecroprop_p, Bayer Advanced Southern Weed Killer for Lawns
dicamba Spectracide Weed Stop for Lawns
Ferti-lome Weed Out lawn Killer
5. 2,4-D, mecroprop, Total Lawn Weed Killer
6. 2,4-D, mcpp, dicamba, Spectracide Weed Stop 2X for Lawns
7. mecroprop_p, 2,4-D, Weed B Gon for Southern Grasses
8. 2,4-D, triclopyr, dicamba Weed B Gon Max Kills Weeds, Not Lawns
9. 2,4-D, Quinclorac, dicamba Bayer Advanced Lawn Weed & Crabgrass Killer
Ferti-lome Weed Out With Q
Ortho Weed B Gon Max plus Crabgrass Control
10. penoxsalum Green Light Wipe Out Tough Weed Killer for Lawns
Table 3. Herbicides for control of Sedges in Home Lawns.
1. imazaquin Image Kills Nutsedge
2. halosulfuron-methyl Gowen Sedgehammer
3. sulfentrazone + Image Kills Crabgrass
Table 4. Preemergent Herbicides for Use in Home Lawns.
1. dithiopyr Greenlight Crabgrass Preventor2
Hi-Yield Turf & Ornamental With Dimension
Vigoro Weed Stop Crabgrass and Weed Preventor
2. pendimethalin Scotts Halts Crabgrass Preventor,
Lesco Crabgrass Pre Plus Potash (0-0-7)
3. oryzalin Southern Ag. Surflan A.S.
4. isoxaben Portrait Broadleaf Weed Preventor
5. benefin + oryzalin Green Light Amaze Grass & Weed Preventor
6. benefin + trifluralin Hi-Yield Crabgrass Control with Balan
Southern Ag. Team 2 G
7. corn gluten meal Concern All Natural Weed Preventor Plus
Nature’s Guide Corn Gluten Meal
Spring Cultural Practices:
1. Fertilization: In the spring, wait until the turfgrass is green and actively growing before applying the
first application of fertilizer. Apply approximately 1.0 lb. of actual nitrogen per 1,000 sq.ft..
Ideally, amount of phosphorus and potassium applied along with the nitrogen should be determined
by soil test results ( fertilizer ratio). Many of our soils in Texas are high to very high in phosphorus
and potassium and in these cases all you need to apply is straight nitrogen. If a soil test has not been
conducted, then recommend a 4-1-2 to 3-1-2 fertilizer ratio. Not all soils are high in phosphorus and
potassium and if you are applying only nitrogen, then the turfgrass will become stressed.
In heavily shaded areas, apply 0.5 lbs. of total nitrogen per 1,000 sq.ft., unless this is the only
application that is going to be applied to the heavily shaded portions of the lawn. Excess nitrogen
in shade will eventually cause major problems with the turfgrass growing in these areas.
Depending on type of turfgrass, soil type, environmental conditions (sun vs. shade) and level of
maintenance desired, make a second application in approximately 5 to 6 weeks after the spring
2. Mowing: As previously mentioned, mowing the lawn at a lower height and more frequently will
force the turfgrass to spread faster and form a denser stand of turfgrass. The key is to mow the
turfgrass often enough so that you never remove more than 30 to 40% of the leaf blade when the
grass is mowed. Removal of excess leaf tissue inhibits the plants ability to carry on photosynthesis
properly, which means that the plant cannot produce enough food for new growth, especially new leaf
Mowing frequency is going to be determined by height of cut and growth rate. The lower the grass is
mowed, the more frequently it needs to be mowed. The more the grass is fertilized and watered, the
more often it will need to be mowed. Mowing at the proper height and frequency will produce a
denser stand of turfgrass, a deeper root system and more stored carbohydrates in the plant.
Listed below are the recommended mowing heights and frequency for turfgrasses growing in home
Lawns. Note, frequency will vary during the year due to day length differences and due to changes
in temperature. In fall and spring, when we have longer nights and cooler nighttime temperatures, the
warm season grasses are not going to be growing as fast as they will in late spring through early fall
Recommended mowing height and frequency for turfgrasses growing in home lawns.
Turfgrass mowing height mowing frequency
Common bermudagrass 1.5 to 2.5 3 to 4
Hybrid bermudagrass 0.75 to 1.5 2 to 3
St. Augustinegrass (sun) 2.0 to 3.0 3 to 5
St. Augustinegrass (shade) 3.0 to 4.0 6 to 7
Centipedegrass 1.5 to 2.0 4 to 5
Zoysiagrass (japonica) 1.0 to 2.0 4 to 5
Zoysiagrass (matrella) 0.5 to 1.5 3 to 4
Buffalogrss 2.5 to 4.0 5 to7
3. Irrigation: As previously mentioned, it is very important to provide adequate moisture for good spring
transition of the warm season turfgrasses. Applying approximately one inch per week if adequate
rainfall does not occur should meet the plants needs. As temperatures start to heat up, then it maybe
necessary to increase the rate of water applied each week. Ideally, the rate of water applied to the
landscape should be based on the PET (potential evapotranspiration ) rate for the week. Note, if you
are not familiar with the ITC-TexasET Network, this is a excellent site for finding ET rates for different
parts of the state. The web address for this site is: http://texaset.tamu.edu/