FOR THE DAILY SOUTHERNER
Ask A Master Gardener
"As the promise of spring begins to beckon the attention of "dormant" gardeners this time of year, so it is with those dormant weeds that will appear soon enough, making for a lot of catch up work to get our lawns ready for show time," says local Master Gardener Trainee, Bernice Pitt who has just completed certification in an NC State University course in Turf Management. Pitt is manager of the lawn and garden center at Marrow-Pitt Ace Home Center in Tarboro and is ready to help you with solutions in
maintaining your lawn. "I have found that the best source for answers to questions regarding turf grasses is the site:
www.turffiles.ncsu.edu and another,
www.turfweedmanagement.ncsu./weedmanagement.aspx," Pitt added. "It's where we found answers to this week's questions."
Jamie E. (Tarboro) asks: Is it too late to use pre-emergent pesticides to stop weeds in our lawn?
Answer: No, it's not too late. Late winter is when the application of
preemergent herbicides is recommended for summer annual weed control in turfgrass environments. Preemergent herbicides offer a great option for select annual grass and broadleaf weed control in warm- and cool-season turf. Preemergent herbicides are commonly used for crabgrass and goosegrass control but also control other grass and broadleaf weeds propagated from seed. As with any herbicide, one must be mindful of the herbicide mode of action. Specifically, with preemergent herbicides, application timing,
application coverage, and single versus split applications among other factors are crucial to the results obtained.
Since these herbicides control susceptible species as they grow through the herbicide treated zone, the herbicide barrier must be established prior to weed seed germination. In most areas in NC, this occurs in mid- to late-March, so products need to be applied prior to this time.
Common preemergent herbicides labeled for use in turfgrass areas include benefin, dithiopyr, oxadiazon, oryzalin, pendimethalin, prodiamine, and trifluralin (these are common names and are often sold under various trade names). Products like Scott's Halts are readily available at your favorite lawn and garden center and everything you need to know is on the label . An application creates a seal so weeds can't come up. A second application can be applied the first week in April. As with all herbicides, please read the
label and follow instructions.
For weed prevention in your flower beds, ask about Preen at your garden center.
These are two products available at your local lawn/garden center that can be used now to prevent weeds on turfgrass and in your flower beds.
Michael H. (Tarboro) asks: What product can I use to get rid of broadleaf weeds that are already visible on my lawn?
Answer: In many cases, controlling winter weeds in the dead of winter is not a great idea. Once cold weather sets in, winter weed growth slows down significantly. Even nonselective herbicides struggle to kill weeds such as henbit, annual bluegrass and perennials such as white clover when applied in winter months.
Winter weeds will basically go dormant but stay green and survive through snow and ice. When spring and warmer temperatures approach, winter weed growth and development resumes quickly. Spring would be a better time to successfully control winter weeds once they resume growing.
Turfgrasses that have winter weeds in winter months had winter weeds in fall months as well. Whether from procrastination or just the fact that the weeds were so small they were not noticeable in the fall, winter weed control applications are possible in some instances.
Warm-season turfgrasses, especially bermudagrass, allow for winter applications of certain herbicides because of dormancy.
There are several herbicides (selective and nonselective) that are effective on annual bluegrass, various winter annual broadleaf weeds and wild garlic, but could be injurious to transitioning or fully green warm-season turfgrass.
Therefore, the ideal timing for these herbicide applications would be winter months when the turfgrass is dormant. Check actual herbicide labels for the most accurate information concerning turfgrass tolerances, rates, adjuvant requirements, timings and weed species controlled.
Dormant bermudagrass only: annual bluegrass and various annual broadleaf weeds
Roundup, Finale and QuikPro are nonselective herbicides that must only be applied to dormant bermudagrass. Do not apply these herbicides to dormant zoysiagrass, centipedegrass or St. Augustinegrass! Injury (delayed greenup and possibly death) will be observed during spring transition. When temperatures are 60 F or greater, apply Roundup at 0.5 lb ai/A, Finale at 3 to 6 qt/A or QuikPro at 5 to 9 oz/A depending on weed species and size. At
these rates, very few perennial weeds (dandelion, white clover) will be controlled.
Sencor 75 Turf must also be applied to dormant bermudagrass before spring transition or greenup will be delayed. Sencor 75 Turf applied at 0.67 lb/A controls annual bluegrass and various winter annual broadleaf weeds.
SureGuard is a new herbicide from Valent USA Corporation. SureGuard applied to dormant bermudagrass at 8 to 12 oz/A will control annual bluegrass and winter annual broadleaf weeds such as henbit, chickweed, geranium and hairy bittercress. Another benefit of SureGuard is preemergence crabgrass control. With this herbicide, it is possible to control winter weeds postemergence
and summer grasses preemergence with one application. Do not apply SureGuard to actively growing bermudagrass as unacceptable injury will occur!
Wild garlic control
Image 70DG is recommended for wild garlic control in winter months only, because warm-season turfgrasses are affected when transitioning to active green growth. Image 70DG can be applied up to 0.7 lb/A to dormant bermudagrass, centipedegrass, zoysiagrass and St. Augustinegrass.
"Ask A Master Gardener" is a weekly column providing our readers solutions to common problems concerning horticulture, gardening, and pest management. Trained Extension Master Gardener Volunteers have access to the research that provides answers.
Submit your questions by email to <mailto:email@example.com>
firstname.lastname@example.org. Or call the local Extension Center at 252-641-7815 and tell them you have a question for a master gardener; a volunteer will return your call with a solution to your problem, or write to "Ask A Master Gardener", c/o The Daily Southerner, P.O. Box 1199, Tarboro, NC 27886.