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Tag: Weeds

Controlling Grassy Sandbur

Posted on by djbechard

Grassy sandbur is the “sticker” plant that looks like a grass. It will often invade thin lawns, especially in dry years. Therefore, the best control for this weed is a thick, healthy lawn. However, if your lawn is thin this spring and grassy sandbur was a problem last year, use a preemergence herbicide before the sandbur comes up. Not all preemergence herbicides are effective. The three products that can help minimize grassy sandbur are oryzalin, pendimethalin and prodiamine.

Oryzalin is sold under the trade names of Surflan and Weed Impede.   It can be used on all warm-season grasses as well as tall fescue. It should not be used on cool-season grasses other than tall fescue such as Kentucky bluegrass. Oryzalin is also sold as a combination product with benefin as Green Light Amaze.  As with oryzalin alone, it can be used on all warm-season grasses as well as tall fescue. It should not be used on cool-season grasses other than tall fescue such as Kentucky bluegrass. Apply Amaze or an oryzalin product about April 15 when redbud trees approach full bloom.

Pendimethalin is sold commercially as Pendulum as well as several other names. On the homeowner side, it is sold as Scotts Halts. Pendimethalin is best applied as a split application with the first half applied about April 15 and the second about June 1. Alternatively, make the first application when redbud trees approach full bloom and the second six weeks later.

Prodiamine is sold under the commercial name of Barricade.  It is also sold as a homeowner product Howard Johnson Crabgrass Control Plus with 0.37 Prodiamine  00-00-07.  It can be used on all of our common lawn grasses. Apply as is done for oryzalin, about April 15 or when redbud trees approach full bloom. Only one application is needed per year.

None of the “weed preventers” will give complete control but each should help. Quinclorac (Drive) can provide some postemergence control especially if the sandbur is in the seedling stage. Quinclorac is also found in a number of combination products that control both broadleaf weeds and crabgrass such as one of the following:

Ortho Weed-B-Gon Max + Crabgrass Control

BioAdvanced All-in-One Lawn Weed and Crabgrass Killer.

Monterey Crab-E-Rad Plus

Fertilome Weed Out with Crabgrass Killer

Trimec Crabgrass Plus Lawn Weed Killer

Bonide Weed Beater Plus Crabgrass & Broadleaf Weed Killer

Spectracide Weed Stop for Lawns Plus Crabgrass Killer

 

Again, the best control for grassy sandbur is a healthy, thick lawn.

By: Cassie Thiessen

Crabgrass Preventers

Posted on by mjsaxton@ksu.edu

Crabgrass preventers are another name for preemergence herbicides that prevent crabgrass seeds from developing into mature plants. Many people have a somewhat foggy idea of how they work and assume they kill the weed seed.  Such is not the case. They do not kill the seed or even keep the seed from germinating but rather kill the young plant after it germinates.  Therefore, they do not prevent germination but prevent emergence.

Crabgrass preventers are just that – preventers. With few exceptions they have no effect on existing crabgrass plants, so they must be applied before germination. Additionally, preventers do not last forever once applied to the soil.  Microorganisms and natural processes begin to gradually break them down soon after they are applied. If some products are applied too early, they may have lost much of their strength by the time they are needed. Most crabgrass preventers are fairly ineffective after about 60 days, but there is considerable variation among products.

For most of Kansas, crabgrass typically begins to germinate around May 1 or a little later. April 15 is normally a good target date for applying preventer because it gives active ingredients time to evenly disperse in the soil before crabgrass germination starts.  Even better, base timing on the bloom of ornamental plants. The Eastern Redbud tree is a good choice for this purpose. When the trees in your area approach full bloom, apply crabgrass preventer. A follow-up application will be needed about 8 weeks later unless you are using Dimension or Barricade. Products that do require a follow-up application include pendimethalin (Scotts Halts) and Team (Hi-Yield Crabgrass Control).

We recommend crabgrass preventers be applied before fertilizer so that the grass isn’t  encouraged to put on too much growth too early. However, it may be difficult to find products that contain preemergents without fertilizer. Those that don’t contain fertilizer are listed below.

Barricade – Howard Johnson Crabgrass Control Plus with 0.37 Prodiamine 00-00-07

Pendimethalin – Scotts Halts

Team (Benefin + Trifluralin) – Hi-Yield Crabgrass Control

Dimension – Hi-Yield Turf & Ornamental Weed and Grass Stopper

By: Cassie Homan

Crabgrass Preventers

Posted on by Marci Metz

Have you struggled with weeds in your lawn, flower beds, and garden? Crabgrass is a very common Kansas weed that seems to thrive in our hot summer weather. Get ahead of weeds this year by applying a preemergent herbicide. The best time to apply is around the middle of April or when the Redbud trees in your area start to bloom.

Read our latest blog for more information: http://postrockextension.blogspot.com/2019/03/stop-crabgrass-before-it-starts-growing.html

By: Cassie Homan