Questions & Answers on the usage of Weed Impede™ (Surflan^®), formerly Weed Stopper^®

What is Weed Impede?

Weed Impede is 40.4% active ingredient based on Surflan^® (oryzalin), a widely used agricultural herbicide. It is classified as a preemergence, surface applied herbicide.

What does Weed Impede do?

It controls weeds in your landscape ornamental areas for up to 6 months.

What weeds does Weed Impede control?

Weed Impede is primarily a grass killer. However, it is quite active on broadleaf weeds such as pigweed, purslane, spurge, oxalis, and many others.

How much Weed Impede do I use?

The recommended rate of application is 1½ - 3 oz. per 1000 sq. ft. in sufficient water for coverage. Two gallons of spray will cover approximately 1000 sq. ft., so add 1½ - 3 oz. Weed Impede in your 2 gallon sprayer, shake well and spray.

Once Weed Impede has been sprayed, what do I do?

Weed Impede must go into the soil to be effective. If you are in a high rainfall area there is no problem. In other areas, Weed Impede may be moved into the soil using sprinklers. You can wait up to 21 days to do this, but the sooner it is done, the better.

Will Weed Impede control weeds that are already up?

No, it only is effective as a preemergence herbicide. If you have a situation where weeds already exist (and no ornamentals have been planted) you might want to consider a tank-mix with Roundup^®. Roundup will kill the existing weeds and Weed Impede will go into the soil to control those that have not yet germinated.

How many times a year should I use Weed Impede?

Most people use the product twice a year, once in the fall prior to the rainy period, and once again in the spring after the bedding plants are put in.

What ornamental trees, plants, shrubs, or ground covers can I use Weed Impede on?

Over 175 species of ornamentals are on the Weed Impede label. These include bedding plants, ground covers, shrubs and trees. You can download the label to check the list out for yourself.

What species should I not use Weed Impede on?

Specifically, Weed Impede should not be used on slender Deutzia, Douglas fir, Techny arborvitae or Eastern hemlock.

What is the best way to use Weed Impede on bedding plants?

The first step is to prepare the beds by rototilling, spading, etc. Plant the bedding plants and then spray Weed Impede over the entire area. Once sprayed, turn on the sprinkler and wash the Weed Impede into the soil.

Can Weed Impede be used in my vegetable garden?

No, Weed Impede is only registered for use on ornamentals. For preemergence control in a vegetable garden you can use Vegetable and Ornamental Weeder (formerly Weed Stopper II). To view this label click here.

Can I use Weed Impede on bulbs?

Yes, Weed Impede can be used on iris, daffodil, narcissus, gladiolus, hyacinth, and tulips. Application should be made 2-3 weeks after planting the bulbs but prior to weed emergence. Do not use on gladiolus corms less than 1 inch in diameter and do not apply to tulips that have emerged over ¾ inch.

Can I use Weed Impede on turf for preemergence control of crabgrass?

Yes, but only on warm season turf species such as bermudagrass, St. Augustine, buffalograss, bahiagrass, zoysiagrass, centipedegrass, etc. Apply only to well established turf and do not plan to overseed for at least 90-120 days following application. If you have cool season turf such as fescue, bluegrass, ryegrass or bentgrass check out our new Crab & Spurge Preventer product. For best result on all types of turf use Crab & Spurge Preventer made from Dimension, for preemergence of crabgrass and many other weeds in your lawn.

Can I use Weed Impede on tall fescue turf?

Yes, but use it very carefully. Do not apply at the single application rate! Apply Weed Impede at a rate of 1 oz./1000 sq. ft. in the initial application followed by 1 oz./1000 sq. ft. 8-10 weeks later. Do not treat tall fescue in the spring or summer if it was seeded the previous fall. Weed Impede can only be used on well-established tall fescue and then carefully as outlined above.

Will Weed Impede stain?

Yes, Weed Impede will cause a bright orange stain on rocks, sidewalks, etc. To avoid this temporary stain, simply wash the material into the soil after application, before it dries.

What rates do I use Weed Impede on warm season turf grasses?

Apply to well establish turf one time in the spring prior to crabgrass germination at 1½ oz. per 1000 sq. feet.

Are there any special instructions for usage on tall fescue?

Yes. On well-established tall fescue apply an initial application prior to crabgrass germination at 1 oz. per 1000 sq. feet. Follow with a second application of 1 oz. per 1000 sq. feet 8 to 10 weeks later.

Can I cultivate or hoe the flowerbeds once I have applied Weed Impede?

Yes, once it has been watered into the soil additional cultivation does not decrease the weed control.

What sizes is Weed Impede available in?

Weed Impede is available in ½ pint, pint, quart, and gallon size containers.

Is it true that Weed Impede is expensive?

Suppose you pay $36.00 per quart for Weed Impede, that equals $2.25 per oz. of material. The application rate is 1½- 3 oz. per 1000 sq. ft., which equals $3.38-$6.75 per 1000 sq. ft. That is very economical for 6 months of weed control. For a little over $1.00 per month you can prevent weeds and save yourself a lot of time weeding your flowerbeds!

Where can I purchase Weed Impede?

Ask for Weed Impede is available from your local retail nursery or garden supply store.

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