Weeds in the Lawn and Garden
Weeds in gravel driveways can be pulled by hand or seared with flame weeders, which are propane torches designed to kill weeds. Available brands include Weed Dragon and Weed Wizard, and generic products are widely available at hardware stores. Flame weeders are especially effective against annual weeds; for perennial weeds, multiple treatments are usually necessary. They are best used when weeds are small, and before they set seed. It’s important not to flame weeds when they are dry and may catch fire.
To use a flame weeder, move the flame back and forth, searing weeds but not burning them. Do not use on bark mulch, plastic, or near flammable debris or dry plants. Keep flame away from feet, hands, or clothing, and move backwards as you work to avoid walking over hot surfaces. Keep a fire extinguisher or water supply handy.
If it is impractical to pull weeds manually or to sear them with a flame weeder, less-toxic herbicides can be used. Various products are available and can include acetic acid (vinegar), eugenol (clove oil), or fatty acids as active ingredients. These products only damage portions of plants that they directly contact, and also do not distinguish between broad-leafed weeds, grass, and ornamental plants. They are most effective for killing annual weeds, and repeated applications may be necessary for perennial weeds. If you choose to use a less-toxic herbicide, be sure to read and follow label directions, and to store it in a safe place away from children and pets.
For more information please read our Weed Management fact sheet (39kb PDF file).
Vinegar for Weed Control
Some people have found vinegar to be an effective non-selective, contact herbicide (weed killer). In fact, some commercial herbicide products are available that contain acetic acid (vinegar) as an active ingredient. In the ready-to-use formulations, the concentration of acetic acid in these products is about the same as in regular household vinegar. Advantages of using household vinegar are its low price and the fact that it doesn’t contain undisclosed “inert” ingredients. However, straight vinegar is less effective than the commercial products because the commercial products contain a surfactant that allows the products to wet the leaves better. Another disadvantage is that vinegar doesn’t come with an EPA-approved label with directions and safety information.
We generally don’t encourage people to concoct home-made pesticides, but don’t have any problems with people trying vinegar as a less-toxic weed killer. Bear in mind that being non-selective, vinegar may kill desirable plants such as grass or ornamentals. Vinegar also only affects parts of plants that come into direct contact with it, so spraying it on leaves or stems won’t affect the roots unless some of it happens to trickle down to the soil, and even then there’s no guarantee that roots will be affected.
For more information on less-toxic herbicides, please see our FastFacts: Weeds in Gravel Driveways (at the top of this page).
For more information on weed management, please read our Weed Management fact sheet (39kb PDF file).
Renovating a Weedy Lawn Without Pesticides
In the maritime Northwest, spring (April to mid-May) or fall (mid-September to mid-October) are the best times to renovate. Lawn renovation involves the following steps: aerating to reduce soil compaction and improve water infiltration, overseeding to thicken turf and fill in bare spots where weeds may take hold, topdressing with compost to add nutrients, support soil life, and improve drainage, and for lawns that have accumulated more than 1/2 inch of thatch, de-thatching.
The use of herbicides is not necessary in lawn renovation, though it may be useful in cases where weed cover is extensive. In such cases, repeated spot treatments with less-toxic herbicides prior to starting the above steps may be helpful. Physical removal of weeds with long tap roots (such as dandelions) will also be beneficial; long handled pincer-type tools are available for this purpose. In cases where weeds make up over 50% of a lawn and soil is very poor, complete removal and replacement may be warranted.
For more detailed instructions on lawn renovation and removal, please see:
Bear in mind that the best way to keep weeds out of your lawn is to grow thick, healthy turf. For information on lawn care and lawn removal, please see our Lawn Care fact sheet (38kb PDF file).
Invasive or Noxious Weeds
As with other weeds, invasive or noxious weeds should be controlled manually if possible. Techniques include pulling, cutting, mowing, cultivating, digging, and grubbing. The most effective techniques vary depending on the type of weed, so it is important to identify the weed and obtain specific instructions. It is especially important to find out whether or not the invasive weed you are planning to control is a noxious weed. Noxious weeds are invasive weeds that are considered to be especially problematic, and control requirements are set by noxious weed control boards. In Washington, Class A noxious weeds must be controlled throughout the state, but requirements for Class B and C weeds vary among counties. The best sources for information on noxious weed identification and control are your county and state noxious weed control boards:
Other sites for information on invasive weeds:
In some cases, physical controls may be impractical or ineffective, and temporary use of herbicides may be warranted. If possible, they should be injected directly into stems, or wiped onto cut stems (be sure to check what methods are appropriate for your weed and the product chosen). These methods decrease the amount of herbicide used as well as the amount dispersed into the environment, and are preferred over spray applications. Goats, available for rental, can also be helpful in some cases.
Also, when choosing plants for your garden, make sure not to plant invasive or noxious weeds such as English Ivy that are still available at nurseries.
Moss in Lawns
Although often considered a weed, moss is actually a native plant. If moss thrives in your lawn, it means that conditions favor moss over turf. If you don’t address those conditions, your efforts at moss control will be temporary at best. Moss does well in shady, moist soil with a slightly acid pH. Grass likes sun, soil that dries out between waterings, and alkaline pH. You can help your grass outcompete moss by pruning trees to let in more light, solving drainage problems, and liming the soil. Consider replacing grass with other groundcovers or plantings in deep shade, on slopes, or in boggy areas.
Once the conditions above have been corrected, moss can be raked out fairly easily and the area overseeded to thicken the turf. With this approach, chemical controls may not be needed at all.
Chemical controls for moss include iron sulfate and moss-killing soaps. Soap-based products are rapidly biodegradable and relatively non-toxic. Always use any pesticide according to label directions. Iron sulfate is fairly benign, but avoid products corrosive to eyes, identified with the word “Danger” on the label. Also, be aware that iron will stain sidewalks.
For more information on moss control, please read our fact sheet Tales from the North Side: Problems with Moss (500kb PDF file).
Moss on Roofs, Decks, and Sidewalks
Moss or algae form on roofs, decks, sidewalks, and other hard surfaces that are located in shady areas. They can damage roofing materials and cause water leakage, make sidewalks and decks dangerously slippery, and cause staining.
Moss can be removed from decks and sidewalks by scraping or by pressure washing. The latter approach is not advised for roofs because it can damage or get under shingles. A leaf blower can be used to remove moss from roofs during the dry season. Once heavy buildup has been removed, chemical moss killers can get the rest and provide some residual protection.
Moss-killing soaps, such as Safer™ brand, are among the least-toxic options. They also have the advantage that because they are soaps they also clean very effectively. Zinc and copper-based products are potentially a risk to aquatic organisms and should not be used if roof runoff has a direct path to a lake, stream, or storm drain. Some zinc and copper products are formulated with solvents that are toxic to inhale.
For more information on moss control, please read our fact sheet Tales from the North Side: Problems with Moss (500kb PDF file).
Mulching for weed control
A mulch is a layer of organic material that is placed on the soil surface around plants to add nutrients, retain moisture, reduce runoff and soil erosion, and prevent weeds. Around annuals and vegetables, apply 1-3” of leaves, compost, or glass clippings. Around trees, shrubs, and woody perennials, apply 2-4” of woody mulches like wood chips or bark. If you have a choice between wood chips and bark, wood chips are preferred because bark contains waxes that prevent absorption and release of water, is sometimes contaminated with weeds or salt, and softwood bark (such as from Douglas fir) contains sharp fibers that can be painful to work with. Mulches should be spread around plants to the drip line (the diameter of plants’ outermost branches) or can cover an entire garden bed. It’s important to keep mulch a few inches away from the trunks of trees and shrubs.
Though mulch can prevent the germination of weed seeds smothered below it, do note that some types of mulch, such as hay and bark, can be contaminated with weed seeds. (Straw and wood chips are less likely to be contaminated.) Weed seeds can also blow in on top of mulch after it is applied and germinate; however, weeds are usually easier to pull from mulch than from soil.
Mulch can be applied at any time, but early spring, before soil moisture has evaporated, is an especially good time. It’s a good idea to weed the area before applying. Lawns can also be ‘mulched’ by leaving behind clippings when mowing; mulching mowers that blow clippings back into the ground are available. Compost is also an excellent soil amendment for turf.
For more information on mulch see the King County fact sheet Make the Mulch of It (288kb PDF file).
Weed Dragon Flame Weeder/Weed Torch: Product Review
Tackling weeds seems to be my main focus (or is it an obsession!) in mid-summer and I keep many different specialty weeding tools at hand to attack different weed situations.
One of the solutions is the Weed Dragon garden torch. I purchased the VT2-23SV Combo 100,000 BTU Vapor Torch Kit with the squeeze valve and handcart option about 8 years ago and use it every month during the summer to keep weeds from getting out of control. It is particularly useful along paved or gravel areas where other weeding tools can’t penetrate. I also use it along our fence and in some mulch beds.
Getting the Weed Dragon Ready to Fire Up
The optional squeeze valve.
When you receive your Weed Dragon the wand will be fully assembled. All you need to do is inspect it to be sure all the parts are there and connected according to the enclosed instructions. I have the model with the squeeze valve. That allows me to control the flame setting (high and low) rather than only having one continuous full flame. This feature is particularly handy for spot weeding.
The cylinder dolly will need to be assembled. Simply attach the two tires and the nylon strap that holds the cylinder in place following the diagram that is included with the instructions. Then you attach a propane tank that you need to purchase separately. If you are like me and have a gas grill, you can get an extra tank from your local big box hardware store and then you have one for the grill and one for the Dragon. If either runs out at a critical time, you have a backup.
Connecting the Propane Tank
Attaching the cylinder
Attaching the hose
Testing for leaks
- Check to be sure the O-ring is in place on the nipple fitting of the Dragon wand.
- Make sure the supply cylinder valve is turned fully off and remove the protective plastic plug.
- Insert the nut/nipple fitting into the propane connection by turning counter clockwise. It is a little tricky to get it lined up just right so it screws in. Once it feels snug, don’t over-tighten.
- Test for leaks. I use a spray bottle with water and a few drops of dish detergent. This is sprayed onto the connection and when you slowly turn on the gas by opening the cylinder valve, you should not see any bubbling up of your soapy solution.
Get Ready to Burn
Take a few minutes to read the instructions very thoroughly–particularly the Safety Check List. Some of these items are obvious, but it’s good to remind yourself of all the hazards of working around an open flame. This isn’t a toy and it needs to have a good amount of planning and control before tackling any weeding job. I want you to READ the instructions, so I’m not going to copy and paste them here. But I will list a few top safety tips.
Safety Tips When Using the Weed Dragon
- Avoid loose clothing. Have sturdy shoes that give you good footing.
- Have a partner standing by with a garden hose ready to spray down any areas.
- Practice on a safe area like a gravel path with just a few weeds sprouting through. Get used to the squeeze valve and how the flame goes from the pilot light yellow to an almost invisible blue point.
- Don’t try to burn the weed into ash, but rather just “cook” the green leaves until they wilt away.
- Evergreens are extremely flammable so it’s best to avoid getting close to any conifers.
- Never flame poison plants, particularly poison ivy or poison oak. Smoke from these can be dangerous if inhaled.
- Mulch areas need extra caution (see the Cautionary Tale below).
- Always use a flint lighter to ignite the torch. DO NOT USE MATCHES OR CIGARETTE LIGHTER TO IGNITE THE TORCH. Have an ABC fire extinguisher at hand.
- Follow all the other safely tips in the instructions!
The weeds are “cooked” but the dry bark mulch catches on fire.
Thoroughly water the area and check back a little later to be sure all embers are out.
After feeling quite comfortable using the Weed Dragon for several years, my husband and I got careless. Typically, we work as a team. My husband wheels the cart and flames the weeds, while I stand by with a garden hose ready to put out any flames. But one day we flamed some weeds on a bank that was covered in mulch and it appeared fine for many hours afterward, but over night the unknown smoldering mulch caught fire and started down the slope toward our cedar shed. Fortunately we saw the smoke early in the morning when going out to get our newspaper. It had only burned mulch and one end of a landscape timber. BUT… it would have burned down our shed in a matter of hours had we not caught it.
The lesson here is that some materials don’t appear to be on fire, but they are actually smoldering below the surface. Mulch is particularly dangerous. We still flame our mulched areas, but we thoroughly water down the areas afterwards, and double check it carefully.
Let’s Get Started
Clearing garden beds
Wave the wand a few inches above the weeds. Getting too close can cause the flame to go out due to lack of oxygen.
The next day the grass was dead.
Hauling the dolly around the yard is not difficult, although it’s a little awkward at times. It’s a little heavy to roll up any steep hill and it’s easy to get the long hose tangled in the wheels of the dolly. It’s best to slow down and move the dolly into position and then burn a smaller area, then move into the next position and burn that area, rather than trying to burn and roll at the same time. That’s one reason I like the squeeze valve. It helps to not have the high flame going as you move around.
Don’t try to over reach in each position. When in doubt, shut off the flame while moving the unit around any difficult areas and then relight it when you are in position.
Does the Weed Dragon Really Kill Weeds?
In short, yes. But you may not notice much difference until several hours later (or sometimes days, so don’t get impatient!).
The goal isn’t to fry weeds to a blackened crisp. Instead, you’ll simply heat weeds until the plants wilt.
The high heat “cooks” the interior of the weeds, destroying their ability to move water and nutrients from the roots to the leaves, and vice versa. By robbing the plant of nutrition, you’ve set the stage for a steady decline and, eventually, death. Depending on the size and root structure of the plant, this could take as little as a few hours or as much as several days.
Care and Storage
- Make sure the valves are tightly closed.
- Don’t store your Weed Dragon next to gasoline or any other combustible materials.
- Keep it dry and clean in a garage or shed.
- Before each use inspect the connections and test for leaks.
The website lists other uses for this torch such as melting snow and ice from sidewalks in the winter. I haven’t tried that but it seems like it might work, provided all the melt water can be removed so that it doesn’t just freeze up into a sheet of ice.
Made in the U.S.A
Lacrosse, Kansas is the home of the Flame Engineering company that manufactures this product. They warrant their products to be 100% free of defects.
I give the Weed Dragon a 5-shovel rating for its effectiveness. My use for over 8 years is a testimony to how well made it is. I do feel that it is a potentially dangerous tool and would caution anyone to be extra careful when using it. And obviously keep your children and pets away from it at all times.
Where to Buy It
You can find the Weed Dragon (as well as other torches) on the manufacturer’s website. The model tested runs $192 plus about $21 shipping to most areas of the U.S.
Amazon sells the Red Dragon VT 2-23 SVC 100,000 BTU Weed Dragon Propane Vapor Torch Kit (which includes the torch and squeeze valve). You can buy dolly separately. The total cost for all three is $158 with free shipping.
Gardener’s Supply offers a Mini Dragon™ Weed Propane Torch for $49.95, but it does not include the propane tank.
It appears that many online retailers sell the torch, but not the kit with the dolly. I really can’t imagine using this model without the dolly since the propane tanks are so heavy to haul around.
And now over to you – Have you tried a weed flamer? Any tips or recommendations? Let us know in the comments below.
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Disclaimer – All opinions expressed here are those of the author based on personal experience using the product.
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