Early spring is the time to take care of weeds, BEFORE they germinate. Products vary with some labeled for only turf or only ornamentals or both. You will also have to make sure the product is labeled for your particular turf or plants, since using a product not labeled may harm your grass or plants. So lets take a look at some of the “preemergence” herbicides, meaning of course they keep weeds from “emerging” or germinating.
One of the main factors in using a pre-emergent herbicide is timing. It is essential to use the product before germination of weed seeds. This varies all over the country because of temperature difference. Some products can be used anytime, so that if you weed a certain area you can then prevent weeds from reoccurring. Many products are used in early spring or fall to be most effective for instance, to prevent “crabgrass!”
Usually the higher the rate, the longer it lasts. But not all products work this way.
Many of these are orange or yellow in color and will stain temperarily, the exception being Dimension and Ronstar (not named here)
Post emergent herbicides are specific to killing weeds “after” they germinate so that is the significant difference between the two products.
Some products have both post and preemergent activity, such as Atrazine.
These products are primarily professional products only but many are labeled for residential use and not restricted for homeowner use. Most homeowner products you buy at Walmart, etc. consist of only a small percentage of the active ingredient used in professional products. So here is a list and some of their uses:
SURFLAN- 40.4 % Oryzalyn by S.Ag
Used for both warm season turf and landscape ornamentals. This is probably the easiest and safest to use for homeowners. Orange in color. Controls – many annual grasses and broadleaf weeds Lasts up to 4 months at 1.5 oz. per 1000 sq.ft. on turf Ornamentals- 1.5-3 oz. per 1000 sq.ft.
BARRICADE 65 WG – 65% Prodiamine by Syngenta
Used for both warm season turf (including Seashore Paspalum) and container, field grown and landscape ornamentals. Used in established perennials and wildflower plantings. Yellow in color Controls – many grasses and broadleaf weeds Good crabgrass control – see timing on label. Turf – Ornamentals .37-.83 oz. per 100 sq.ft.
GUARDRAIL 65 WDG, PRODIAMINE 65 WDG= SAME AS BARRICADE 65 WDG
GALLERY 75 DF – 75% isoxaben by Dow Used for many cool season and warm season turf, nursery, field grown and ground cover ornamentals. Bulbs and non-bearing fruit and nut trees. Yellow in color Controls – Broad leaf weeds. Turf – 0.5 0Z. per 1000 sq.ft.
PENDULUM 3.3 – 37.4% Pendimethalin by BASF This is a yellow liquid used for Cool Season Grasses such as Bluegrass, Fescues and Ryegrass and Warm Season Grasses. Controls goose and crabgrass and broadleaf weeds Over the top use on many trees and ornamentals. Turf – Ornamentals 1.3 – 1.8 OZ. per 1000 sq.ft.
PENDULUM AQUACAP – 38.7% Pendimethalin by BASF Yellow Liquid higher active ingredient and same as Pendulum 3.3 supposedly non-staining because liquid is encapsulated and washes off into ground, but it does stain! Turf – Over the top Ornamentals 1.1-2.3 OZ. per 1000 sq.ft.
DIMENSION 2 EW- 24% Dithiopyr by Dow Non-Staining – Used on most cool season and warm season turf, container, field grown and landscape ornamentals. Controls annual grasses and broadleaf weeds, including Poa Annua Good Crabgrass control. May cause injury to certain varieties of creeping bentgrass and fine fescues. Turf – Ornamentals .75 – 2 OZ. per 1000 sq.ft depending on which state you are in. *Do not apply to crops grown for food*
TOWER HERBICIDE – 63.9% Dimethenamid by BASF This is a relatively new preemergent herbicide for professional use on commercial turf and landscape maintenance and Ornamental production, not including use in greenhouses. There is a new label approving residential use on turf. Tower is a shoot growth inhibitor that controls germinating seedlings before or shortly after they emerge. Controls broadleaf weeds, many grasses including crabgrass and sedges, including Yellow Nutsedge. Rate .49-.74 oz. per 1000 sq.ft
SUREGUARD HERBICIDE – 51 % Flumioxazin by Valent For the use in containers and field grown conifers and decidious trees, around established woody ornamentals, in landscapes and to maintain bare ground non-crop areas. Post emergence use. There have been problems reported with this product. Controls mostly broadleaf weeds and crabgrass. Rate 8-12 OZ per acre
SPECTICLE 20 WSP – 20% Indaziflam by Bayer For the control of annual grasses, annual sedges and broadleaf weeds in turfgrass, landscape ornamentals, hardscapes, christmas trees. This product is also reported to have problems, probably due to the small amount used per acre. Do NOT use on Creeping Bentgrass, Fine Fescue, Annual and Perenial Ryegrass and Annual Bluegrass. Rate 2.5 OZ. per acre
All products are available at Tampa Agricultural Products. Not all are shown on the website but you can call 1-800-373-5008 to order. Not all preemergent herbicides were named and more can be obtained at Tampa Ag www.tampaag.com