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PUTTING THE YARD AND GARDEN TO BED FOR THE WINTER

GARDEN TIPS – written by Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA Written October 25, 2015

I occasionally get asked to give a presentation on “putting the yard and garden to bed for the winter.” Fall garden chores are pretty simple and can be designated as “should-do” and “good-to-do”. I am not sure I could give a thirty minute or longer presentation, but here are the “should-do’s” for fall.

RAKE LEAVES: On the should-should do list is raking leaves. If you have a number of trees like I do, the leaves can certainly pile up. They tend to blow around and pile up at my back door and elsewhere in the landscape. As we start to get more dew and moisture, these leaves can mat down and smother the grass and other plants. Get those leaves raked up and consider using them for making compost or tilling them into your vegetable garden soil where they will decompose over the winter and help improve the soil.

MOW THE GRASS: After the stress of a very hot summer, your lawn needs all the help it can get. You should keep mowing if the lawn is growing. Do not mow the grass extra short and then put the mower away. Also, do not leave it extra long, as this can lead to matted grass and favorable conditions for snow mold. (This past spring snow mold fungus showed up in many area lawns and caused significant damage.) Mow at the recommended height of about 2.5 inches until you no longer need to mow. The good news is that as the weather cools, you will not need to mow as often.

TREAT FOR BROADLEAF WEEDS: If broadleaf weeds, like dandelions or clover, have shown up all over your lawn, now is the time you should treat for these weeds with an herbicide spray. However, if you only have a few of these weeds here and there, dig them out by hand or pop them out with a “weed popper.”

Herbicide sprays for broadleaf weeds will not control grassy weeds. Annual grasses, such as crabgrass will die with a hard frost, and need to be controlled next spring with pre-emergent herbicides or “preventers” that will keep the seed from germinating and growing. Perennial grasses, such as Bermuda grass, are not controlled with fall chemical applications.

DIG TENDER BULBS: Many of the tender bulbs, corms, rhizomes, and tubers that we plant in our gardens, including cannas, calla lilies, gladiolas, and dahlias, are tropical plants from warmer climates (Zones 7 to10) where they can stay in the ground over the winter. In cooler climates (Zones 6 and lower) like ours, they should be dug each fall and stored for the winter in a cool, dry protected location where they will not freeze. Some years in our area these tubers and bulbs may survive if left in the ground and heavily mulched. However, if winter brings severely cold temperatures, they will be killed.

To store them, wait about two weeks after frost kills their tops and then carefully lift the tubers, rhizomes or corms from the soil; shake off as much of the soil as possible; rinse them with clean water; and let them dry in a protected dry spot. Place them in cardboard boxes or paper bags using dry sawdust, wood shavings, or peat moss for packing.

You know, maybe I could give a talk on getting your yard and garden ready for winter. There seems to be a lot to do in the fall. More soon on the “good-to-do” fall garden tasks.

HERBICIDES CAN CURL LEAVES TOO

written by
Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA
published- JUNE 6, 2014

HERBICIDES CAN CURL LEAVES TOO

This is the time of year that weeds get our attention. As soon as warm weather hits they grow ‘like weeds.’ Then out come a variety of herbicides (weed control chemicals) aimed at killing these unwanted pesky plants in our lawns, landscapes, and gardens. Unfortunately, not using these chemicals properly can injure or kill our desirable plants.

Symptoms of herbicide injury vary depending on the chemical, but common culprits are the growth regulator type herbicides used to kill broadleaf weeds, like dandelions, in lawns. Exposure to the growth regulator herbicides can cause leaf cupping, twisted or distorted growth, and strap-like leaves. The common growth regulator herbicides found in home garden products for lawns are 2,4-D, MCPA, MCPP, and dicamba.

These products are available in liquid form for spray application or in a dry form for applying as a granular. It is very easy to awry when using them in liquid form because wind will cause the spray to drift away from the application ‘target’ area.

To minimize drift, herbicide sprays of any type should only be applied when there is no wind. In our region where it is frequently windy or breezy, this is difficult. The potential for drift can also be reduced by using large spray droplets instead of a fine mist and applying the spray as close to the ground as possible.

The other application choice is a granular herbicide, but desirable plants can still be damaged because of uptake of chemicals through the roots. The labels of products containing dicamba indicate that it should not be used ‘in the root zone of desirable plants.’

If you have trees located in or adjacent to your lawn, it is virtually impossible to avoid applying the chemical in their root zone. The root systems of trees can go out as far as a tree is tall and even further. Garden plants situated next to a treated area could also become damaged via root uptake.

Garden plants can also be exposed to herbicides when grass clippings from recently treated lawns are used as a mulch in the garden. Check product labels for how long you must wait before using the clippings in your garden after application. If you place treated clippings in a compost pile, it is best to compost them for several months before using the compost in the garden.

Other ways to reduce the chance of herbicide injury in the yard and garden include:

1. Avoid applying herbicides in late spring and summer. Herbicides can vaporize during warm (above 80 degrees) weather and float in the air, settling down on plants a long way from the point of application and causing damage. If you plan on using either granular or spray herbicides, do it when the weather is cool in early spring or fall.

2. If you have just a few weeds in the lawn, spot treat them individually or dig them out. A ‘weed popper’ tool works great for this.

3. In landscape beds, apply a three to four inch layer of bark mulch to discourage weeds.

4. In and around the vegetable and flower garden beds use shallow cultivation or simply pull the weeds. I like a stirrup type hoe with an oscillating head. Cultivate frequently to get the weeds when they are small. It is much easier.

I noted last week that the two main causes of curled leaves on garden plants were aphids and herbicide injury. Now we have covered both these culprits.

Published: 6/6/2014 11:43 AM

AVOIDING HERBICIDE INJURY TO PLANTS

written by
Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA
Published 5/24/2013

When weeds appear in the home lawn and landscape many homeowners quickly turn to chemical weedkillers to take care of the problem. Herbicides (weedkillers) kill plants. That is what they are supposed to do. When used correctly they can be an effective tool to use in weed management, when used improperly they can damage desirable plants in your landscape or your neighbors’ yards.

Before you reach for a weedkiller, here are some guidelines for using these chemical tools,

1. Read the label, the entire label, before using the product. Many of the ‘weed and feed’ products or broadleaf weedkillers contain a combination of 2,4-D, MCPP, and dicamba. Somewhere on the label of these products it will note that they should not be used in the root zone of ‘desirable trees and shrubs.’ If you have a landscape with established shade trees in the lawn or in landscape beds bordering the lawn, you will be applying these materials in the root zone of ‘desirable trees and shrubs.’

So what can you do if you have weeds and trees in your lawn? If you just have a few weeds here and there, don’t use an herbicide product over the entire lawn. Spot spray the individual weeds or dig them out. I like the ‘weed popper’ tools like Fiskars Uproot Lawn and Garden Weeder or Grampa’s Weeder (grampasgardenware.com) that use leverage to pop out the weeds along with most of their roots. This avoids tedious back-breaking digging with a hand weeder.

3. Damage to plants from weed killers can also be caused by drift that occurs when sprays are applied when it’s windy. It is hard to find a calm day in this region, but you should never apply sprays of herbicides when the wind speed is over 15 mph. It’s best to wait until the wind is 5 mph or less. Also, the larger the droplet size, the less likely the material will drift off target.

2. If you’re not using a RTU (ready-to-use) product in a spray bottle, it’s wise to use a separate garden sprayer for herbicide sprays. If a sprayer is not cleaned thoroughly after using an herbicide before using it to apply an insecticide or fungicide, you can end up damaging your plants with a contaminated sprayer. To clean a sprayer:

– If you can’t use all the material you have mixed, spray it somewhere in the landscape where it won’t harm plants. Check the label to determine what areas are ‘safe.’ Do not store any mixed product in your sprayer.

– Check the product label for specific directions on how to clean the sprayer after using the product. If there are none, thoroughly rinse the tank, hoses, wand, nozzle, and any other parts with water. Spray the rinse water over a wide area that will not cause damage. Don’t dump it on the ground or down the drain.

– After cleaning the sprayer when using 2,4-D or a similar herbicide, fill the tank with water and add ammonia (1/3 cup of ammonia per gallon of water). Allow it to soak for 24 hours, being sure that the ammonia solution is also run through the sprayer and all its parts before soaking. This will remove much, but not all, of the 2,4-D from the sprayer.

I have already seen damage on local yard and garden plants this spring that could have been avoided if everyone was just being a little more careful and following these simple guidelines when using herbicides.

Published: 5/24/2013 2:44 PM

NEW HERBICIDES HAVE PROMISE FOR CONTROL OF WEEDY LAWN GRASSES

written by
Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA

A couple of weeks ago I mentioned that there wasn’t any herbicide available for selective control of Bermudagrass in Kentucky bluegrass lawns. Until now, the only option was the use of glyphosate (Roundup and other products) to spot treat patches of Bermudagrass or to kill the entire lawn and start over. Dr. Rick Boydston, Weed Scientist for USDA-ARS at WSU Prosser, sent me a note to alert me that there is a chemical available to homeowners for selective control of Bermudagrass in lawns.

The chemical is fenoxaprop‑p‑ethyl. It’s contained in two Bayer homeowner products and is labeled for use in Washington. The two products are Bayer Advanced Bermudagrass Control-Lawns RTS (Ready-To-Spray) and Bayer Advanced Crabgrass Killer-Lawns RTS. They have the same active ingredient, but one has directions for Bermudagrass control and the other for crabgrass control.

The label indicates that one bottle treats 5000 square feet of lawn. That’s the good news. The bad news is that it may take up to seven applications of the product spaced one month apart to control Bermudagrass!

Applications should start in spring when the grass starts to green up and should stop when the Bermudagrass goes dormant in the fall. This is because fenoxaprop‑p‑ethyl works by being absorbed by green leaves and translocated throughout the plant. Don’t expect immediate results. It will take from 4 to 10 days before any visible symptoms, characterized by yellowing or reddening of the leaves, will appear.

You may not be able to get all seven applications in during the same season and may need to continue the applications the following year. However, Boydston indicated that he found that about four applications did a good job controlling the Bermudagrass in his lawn.

Another new herbicide is available to homeowners, but not as readily available as the Bayer products. This product is called Tenacity. Tenacity is labeled for selective control of creeping bentgrass in Kentucky bluegrass lawns. It’s marketed and labeled primarily as a commercial turfgrass product by Syngenta, but it is legal for use on home lawns.

I know of one local homeowner who has used it for bentgrass control and is happy with the results. In addition to bentgrass, Tenacity is also labeled for control of a variety of broadleaf weeds., plus it provides pre and post emergence control of crabgrass, yellow foxtail, and barnyardgrass.

Tenacity contains mesotrione a new chemical that kills weeds by inhibiting the synthesis of chlorophyll. It’s applied as a spray and is absorbed through both the leaves and the roots. Weeds will stop growing after the application, turn white, and die within three weeks. A second application may be needed for control of existing weeds. When trying to control bentgrass in Kentucky bluegrass, research indicates that repeat applications of Tenacity will be needed and that the second application should be applied two to three weeks after the first.

Since Tenacity is intended primarily as a commercial product, it’s not as easy to use. Application rates are indicated as ounces per acre, so your math skills will need to be utilized. Be sure to calibrate your sprayer before applying the material, plus you’ll need a surfactant for controlling existing weeds. For safe and effective use of Tenacity, read and heed the warnings on the label.

These are two new chemicals that offer great promise for control of tough grassy weeds in lawns, but it’s important to understand how they work and to follow label directions.

Published: 9/28/2012 1:10 PM

MORE OF THE WAR ON WEEDS

written by
Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA

Sun Tzu was the expert when it came to the ‘art of war.’ ‘He who knows when he can fight and when he cannot will be victorious,’ also applies to the war on weeds especially, when using chemicals

If you just have a few dandelions or other weeds in the yard, your best bet is to dig them out as soon as they’re noticed. This doesn’t have to be back breaking work. I just ordered a Fiskars Uproot Lawn and Garden Weeder that is supposed to make the job of pulling lawn weeds easy with no bending or kneeling necessary. You just place the steel claws at the end of the long handle over the top of the weed and step on a foot platform. It pops out the weed, roots and all. I’ll let you know how well it works. There are similar tools available at local garden and hardware stores. Pulling may not be practical for extremely weedy or expansive lawns. Also, certain weeds, such as patches of clover or black medic, aren’t easy to pull.

Chemicals are sometimes that only effective way to manage certain lawn weeds, but knowing what, when, and how to use these materials effectively is important.

For broadleaf lawn weeds, like dandelions, plantain, black medic and clover, the right time to apply the appropriate lawn weed killer (herbicide) is fall. Once the weather cools, September through October, is when these perennial weeds are sending food reserves to their roots. Most broadleaf weed herbicides available to homeowners contain a mix of 2,4-D, MCPP (mecoprop), and dicamba (Banvel). When applying a lawn herbicide in the fall, you may think the material hasn’t worked because the weeds don’t die quickly. However, by springtime the weeds should disappear.

Fall is also a good time to apply broadleaf weed herbicides because you’re less likely to damage garden plants through direct misapplication, drift, or volatilization. Also, labels of mixes containing dicamba caution against using them in the root zone of trees and shrubs. Where nearby woody plants may be at risk, it’s a good idea to spot treat the weeds in those areas of lawn.

Many perennial grassy weeds, such as Bermuda grass, in lawns can only be effectively controlled by spot treating with a product containing glyphosate. Glyphosate is a non-selective herbicide that is taken up by green plant tissues and transported down to the roots. The chemical gradually kills the roots and the weed dies. Glyphosate is often the only effective material for managing dastardly tough perennial weeds in landscape beds, such as field bindweed.

Here are some tips on using glyphosate effectively:

Apply to actively growing, healthy perennial weeds that aren’t drought stressed.

The more green leaf surface that’s treated with glyphosate, the more chemical gets into the plant, and the more effective the treatment. Don’t mow or pull weeds immediately before treatment and don’t mow or pull for at least seven days after applying.

When treating Bermuda grass, the most effective time of year is late summer when it’s flowering.

When treating field bindweed in landscapes, the most effective time of year is right after it begins to flower in early summer and then again when runners reach a foot in length.

Avoid getting glyphosate on nearby landscape plants by shielding them with a large piece of cardboard.

Remember to follow Sun Tzu’s advice and know when you can and can’t fight weeds with chemicals.

Published: 9/7/2012 12:48 PM

NEW LAWN HERBICIDE CALLED TENACITY

written by
Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA

Last year one of my columns was titled “Tenacity Key to Controlling Bermudagrass in Landscape .” Little did I know that a newly introduced herbicide has the name “Tenacity.” Unfortunately, this new herbicide isn’t the key to Bermudagrass control, but it does provide control for a number of other broadleaf and grassy lawn weeds.

The active ingredient in Tenacity is mesotrione produced by Syngenta who says the chemical is based on a naturally occurring compound produced by the bottlebrush plant (Callistemon citrinis) that naturally inhibits the formation of carotenoids in susceptible plant species.

Why the bottlebrush plant? Syngenta recounts that one of their scientists noticed that there were fewer weeds growing under his bottlebrush plant, fewer than could be explained by shading alone. This scientist surmised that the plant was probably producing allelochemicals to suppress weed competition. Syngenta investigated and found that bottlebrush does indeed produce allelochemicals. Based on the naturally produced chemicals they discovered, Syngenta was able to synthesize mesotrione for use as a selective lawn herbicide.

How does it work? Mesotrione inhibits a plant enzyme that’s needed for photosynthesis and prevents the formation of carotenoids in susceptible plant species. Lacking essential carotenoids, cell membranes and chlorphyll are destroyed when exposed to light and photosynthetic by-products.

Mesotrione is a systemic herbicide that quickly moves throughout the weedy plants after application. Once it disrupts photosynthesis, plant leaves turn white and within several weeks the plant dies. Not only does Tenacity provide control of at least 46 lawn weeds, including some invasive grasses, it has both pre-emergence and post-emergence activity. It’s safe to use on lawns comprised of Kentucky bluegrass, perennial ryegrass, tall fescue, or fine fescue.

Listen to this… it can be used to control creeping bentgrass, crabgrass, foxtail, goosegrass, nutsedge, and barnyard grass in lawns. It will also provide some pre-emergence suppression of annual bluegrass. Many common and some particularly tough-to-manage broadleaf weeds are also controlled, including dandelion, oxalis, ground ivy, henbit, clover, violets, purslane, lambsquarter, and plantain.

Another nice thing about Tenacity is that unlike many other pre and post-emergent herbicides it can be applied when seeding a new lawn or renovating an old one to prevent weed seed germination.

Other things you should know about Tenacity.

1. Because of possible carryover, you should not use the clippings from a treated lawn as a mulch in the vegetable and flower gardens or beneath trees and shrubs.

2. You should not grow anything other than grass in treated areas for 18 months or more.

3. An application of Tenacity may cause your lawn to turn whitish for several weeks, but the healthy green appearance will return in several weeks.

4. EPA has given Tenacity a registration of reduced-risk status because of its unique mode of action, low use rates, and low impact on human health.

One more thing you need to know is that an eight ounce bottle of Tenacity costs about $80 to $85 via mail-order, but the bottle is enough to treat an acre or more of lawn. This new herbicide is pricey, but if it does its job it may be worth it.

Published: 10/11/2012 11:24 AM

PREVENTING CRABGRASS

written by

Marianne C. Ophardt

WSU Extension Faculty

for the Tri-City Herald, Kennewick, WA

I’m confused. Our university experts in the past have recommended applying crabgrass pre-emergent herbicides or “preventers” when soil temperatures reach about 50 to 55 degrees and stay there for a week or so. They have pointed out that this seems to correspond with the flowering of forsythia. However, other researchers report different optimum soil temperature for germination. Varying research indicates that peak germination occurs at 50 to 75 degrees. That’s quite a range!

Some of this may be due to regional variations or due to the difference in crabgrass species, but it might also be due to germination conditions. Research at Cornell University and the University of Maryland indicates that crabgrass germinates later in dense turf when soil temperatures reach 73 degrees. They also found that crabgrass germinates earlier in thin turf with gaps between plants. Apparently this allows the soil to warm up more quickly and most of the crabgrass will germinate sooner over a shorter period of time.

While interesting, does this mean that lawn owners should change the timing of their crabgrass preventing chemical applications? Should they measure the soil temperatures before applying the chemicals. Not really. It’s still best to apply “preventers” in early spring about the time forsythia starts to drop its blooms.

Of course, everyone is tempted to apply chemicals when forsythia starts to bloom which will be very soon. This is only a problem if you use a product that contains pre-emergent chemicals that aren’t very persistent and don’t last long in the soil. WSU recommends the pre-emergent herbicides of benefin, trifluralin, and pendimethalin for crabgrass prevention.

Check the label of any product you apply to see how long it’s supposed to be effective. Those with longer persistence are more forgiving if you apply them a little early, but those with only several weeks of efficacy may not last long enough if cooler weather returns and slows the germination process. Also, be sure to read the label regarding the rate of application and any other application directions, such as the need for watering right after application. If the product requires water for activation and you have no way of watering your lawn, it will not be effective. For good control be sure to apply the material evenly at the recommended rate for good coverage.

Just last week one of our WSU Master Gardeners was trying to help a friend understand the label of a particular crabgrass control product. He called me puzzled because the product label wasn’t very informative and seemed to indicate that it was applied to crabgrass after emergence. He was unaware of home garden products available for killing crabgrass plants after they germinate or “post-emergence”. Most of these materials contain MSMA (monosodium methanearsonate.) While available to home gardeners, these organic “asenicals” must be applied early in the season when the crabgrass plant is small with only three to five leaves. They are not effective against larger, older grass plants…and that’s the time when most people notice that their preventer didn’t work.

IS IT REALLY CRABGRASS? In our region, many homeowners mistakenly think they have a problem with crabgrass, an annual that comes up from seed every year. That’s why “preventers” are applied in the spring. However, many folks actually have problems with Bermuda grass in their lawns. This tough warm-season perennial starts to grow from dormant roots, rhizomes, and stolons after the weather warms up. If you think it’s crabgrass, but it has tough wiry root and stems when you try to pull it up, it’s probably Bermuda grass. We’ll tackle it’s control another time.

Published: 3/17/2007 10:27 AM

FALL IS GOOD TIME TO KILL DANDELIONS

written by

Marianne C. Ophardt

WSU Extension Faculty

for the Tri-City Herald, Kennewick, WA

As a youngster, I used to delight in lawn dandelions. They had such a pretty yellow flower and it was so much fun blowing on the fuzzy “flowers” and making a wish. Remember? You may also remember dandelions spoiling your dream of a picture-perfect green lawn last spring. Remember? Fall is an excellent time to control a number of perennial lawn weeds, such as dandelions, chickweed, plantain, black medic, clover, and ground ivy.

If you only have a weed or two in your lawn there usually is no need to apply chemicals for control. Hand-weeding is the most practical and environmentally friendly way to take care of a weed here or there. Use a dandelion digger to dig out thick taprooted plants… such as dandelions. If there are weeds throughout your lawn, you may find that chemical control is more practical than weeding by hand.

Before you can utilize chemicals effectively, you should first identify your weeds. If in doubt, bring a sample of the weed in question to the Master Gardener Plant Clinic in Kennewick. Once you know your weed, find out what controls it best. The Master Gardeners can help with this too.

For broadleaf weeds, there are selective herbicides which can be applied to the lawn that will kill susceptible weeds and not hurt the grass. Common lawn herbicides contain 2,4 D, mecoprop (MCPP), or dicamba, often altogether in one mix. (This mix is sometimes referred to as “trimec.”) Mixes are often used because certain weeds are more susceptible to certain herbicides and not as susceptible to others. A mix provides control of a broader spectrum of weeds. This is convenient if you have a number of different types of broadleaf weeds in your lawn.

The ingredient dicamba provides control of some hard-to-kill weeds that 2,4 D and mecoprop don’t control, such as henbit, ground ivy, and black medic. However, if you use a material containing dicamba, pay very close attention to the label warnings. Dicamba should not be used in the root zone of desirable trees and shrubs because it can cause serious injury to these plants. The roots of trees can go out as far, or even farther, than the tree is tall. Keep this in mind when using any product containing dicamba.

There are also some special herbicide mixes that contain yet another ingredient, triclopyr. It’s particularly good in controlling spurge, oxalis, and violets. You also need to be careful applying this material around trees and shrubs. As with any type of herbicide, read the label and follow the directions carefully. If applying the materials as a spray, never spray when conditions are hot or windy. If you only have certain areas of the lawn that contain troublesome weeds, apply the herbicides only to these areas. There is no need to apply it to areas that are weed free.

Late summer and early fall are also a good time to control perennial grassy weeds, like quackgrass, with glyphosate. Unfortunately, glyphosate is non-selective. It kills both the undesirable (weeds) and desirable plants to which it’s applied. This means that you need to spot-treat perennial grassy weeds with a product containing glyphosate. At this time of year, the grassy weeds are moving their carbohydrate reserves from their leaves to their roots and a glyphosate application tends to be more effective. It’s important to note that “more effective” doesn’t mean total control. It’s likely follow-up applications will be needed next year. If a lawn is overrun with grassy perennial weeds, such as Bermuda grass or bentgrass, it’s usually best to consider renovation. This involves killing the entire lawn now and starting over next spring.

Lawn Care Note: The most important times of the year to fertilize your lawn are early September and early November!

Published: 9/9/2006 11:07 AM

USING GLYPHOSATE

written by
Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA

I don’t know of any gardener who hasn’t heard about Roundup herbicide. Roundup was introduced by the Monsanto chemical company in 1974 and in the last 30 years it has become one of the most widely used herbicides in the world. An obviously popular agricultural herbicide, Roundup has also become a common weed control tool for home gardeners.

Glyphosate, the active ingredient in Roundup, is still marketed by Monsanto-Ortho to home gardeners under the trade name of ‘Roundup,’ but glyphosate is also available to home gardeners under many, many different trade names. These products are just as effective as Roundup and are often less expensive.

There is no doubt that glyphosate is immensely popular. It’s heavily relied upon by home gardeners for control of difficult weeds, such as Bermuda grass, quackgrass, and field bindweed. Unfortunately, a lack of understanding of how glyphosate works and a failure to follow precautions regarding its safe use can lead to inadequate weed control or damage to desirable garden plants.

Here are some tips on using glyphosate effectively and safely in the yard and garden.

1. Apply glyphosate only to dust-free, clean plants. One of the characteristics that makes glyphosate fairly safe to use is that it becomes ineffective when it comes in contact with soil particles. If your target weeds are dusty, the glyphosate will bind to the dust particles and not enter the plant.

2. Glyphosate works by being taken up by green plant tissues and then translocated (moved within the plant sap) to the roots where it inhibits plant growth. It’s important to treat weeds when they’re at their most vulnerable stage of growth. It’s most effective on annual weeds that are fairly young and small, less than six inches tall. On perennial weeds, it’s most effective when applied at the bud to early flowering stages.

3. Since glyphosate is taken up mostly by green leaf tissues, the more leaf surface area to which it’s applied, the more chemical enters the plant… and the more effective the control. Thus, it’s better to have healthy, actively growing green weeds with lots of leaves for an effective treatment. Treatments of glyphosate will be not be effective if applied when weeds are brown and dormant, when they’re stressed from drought, or soon after weeds have been mowed, tilled, or pulled.

4. Always use the rate recommended on the glyphosate product label. Don’t use higher rates than recommended on even particularly hard-to-control weeds. However, these tough weeds may require a second application later.

5. Keep in mind that glyphosate is taken up by green plant tissues. This is typically the leaf, but also includes green stems and bark. Incidences of plant damage can occur when sprays of glyphosate are applied to weeds at the base of plants such as rose bushes, raspberry canes, or young trees. Be sure to shield the bases of these plants from the spray when applying glyphosate.

Published: 5/5/2006 11:20 AM

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