Herbicide Safety
***Please note: This is just an overview of a few points. There is much more to learn! Please carefully read the more comprehensive information that has been beautifully provided by Blue Ridge PRISM.***
The only thing more complicated than figuring out the laws around herbicide use is figuring out how to use them! There are many different products available, with different concentrations and application methods needed for different plant species. It’s essential to get it right, to stay within the law and to protect the environment and yourself. Professionals must take extensive training to obtain their certifications, but unpaid people are on their own.
What laws apply to unpaid people?
In Virginia, as long as money is not exchanged, anyone may apply unrestricted herbicides on a private property other than their own, with the permission/invitation of the property owner. This includes roadside rights of way, with permission from the owner of the land immediately adjacent However, “The label is the law” means that exactly: everything on the label is law that you must follow. The actual labels have teeny print. You can find them online by looking up the product name. The penalties for not following the law are significant.
Virginia is a “label law” state, meaning the regulators just go by the EPA label, unlike some states which sometimes expand upon those regulations. In addition to what is on the label, there are addendums which can be found online, and there are "limited areas” that have extra rules to protect endangered species.
You can look up the labels here: https://npic.orst.edu/NPRO/.
What are the safety concerns?
The most hazardous herbicides are either no longer for sale in the United States or “restricted,” meaning not available to the general public. That leaves several unrestricted ones that you can buy at garden shops or online. To make it safe, you need to take great care not to expose yourself to the chemicals nor get them on plants you didn’t mean to target. Here are a few of the points to consider.
People
There is a huge amount of controversy about how concerned we should be about the low level of exposure that we all get from herbicides in our food or from occasional outdoor use, ranging from “no concern if you take normal precautions” to “causes cancer and neurological injury.”
Glyphosate is the most popular herbicide for invasive plant control, thought to be safer than many alternatives and less expensive: Click here to see a discussion about health concerns..
Triclopyr is the second most commonly-used product for invasive plant control. You don’t want to get any herbicide in your eyes, but a drop splash from triclopyr can actually cause blindness.
Other plants
Glyphosate breaks down in the soil or sunlight and is generally not thought to spread to other plants from the roots of the targeted plant. The same is true for Triclopyr acid or amine, but Triclopyr ester is mixed in oil for basal bark treatment and can reach other plants if it washes off the target.
In addition to the risk of spray droplets drifting onto other plants, some of the herbicide gets volatilized and can drift as a gas to nearby plants, even enough to kill nearby mature trees. This is a particular problem in hot weather or windy days. You avoid this by spraying larger-size droplets, never spraying when it is windy, never spraying anything higher than your waist (or thigh or knee, depending on who you ask), avoiding spills particularly on hard surfaces, and never using any herbicide when the temperature is over 85 (or 80 to be really safe).
WIldlife
Although what really kills pollinators is insecticides, some studies have shown injury from herbicides as well..
Some surfactants, which allow the herbicide to stick to leaves, cause birth defects in amphibians. If you are using a surfactant, be sure it is “aquatic safe.” No surfactant is needed for cut-stump treatments.
To avoid introducing too much herbicide into the environment, each label specifies the maximum amount that can be applied per acre.
Why ever use herbicides if they might cause these problems? It’s a matter of comparing one risk to another.
Some invasive plants such as Tree-of-Heaven and Japanese Knotweed cannot be controlled without herbicide. Attempts at manual control actually make them spread more.
Others could be pulled or dug up, but the soil disturbance can cause erosion and stir up the seed bank, resulting in an explosion of other invasives. Bigger roots may literally require a backhoe and extensive excavation to remove.
It is very difficult to get out all the roots of most plants. You end up having to do it again and again as they regrow. Do you want to rescue the same trees over or over, or move on to help more trees? We estimate that there are around a million trees in Fairfax County in need of rescue.
The amount of time and labor that would be required to control invasive plants without herbicides across 260,000 acres in Fairfax is so enormous as to be unfathomable, not to mention unaffordable by our community.
For the environment, it often comes down to a possible but intermittent risk to non-target species from herbicides versus the total loss of those species in a given area to invasive plants. Our birds, insects, and other wildlife cannot survive without the native plants they evolved with. Many of our natural areas are expected to “fail” by the end of the century unless we intervene, meaning hundreds of thousands of trees will die and not be replaced because of the tangle of invasive plants at ground level. We are already seeing this happen in many parts of Fairfax County. This is why you see thoughtful, experienced environmentalists, who otherwise try to avoid chemicals, using herbicides for this one purpose even if they would never use them just to control weeds in their yards.
Labels
Glyphosate product label - 118 pages!
You really do need to read these! Some of it will be irrelevant for what you are doing and can be skimmed.
Personal Protection Equipment (PPE)
Required PPE is on the label and should be worn when mixing as well as when applying. In all cases, this includes
Socks
Closed-toe shoes (preferably rubber or plastic)
Long-sleeved shirt
Long pants
Chemical-resistant gloves (Double-gloving with disposable nitrile gloves underneath longer 15+ mil gloves is quite helpful.)
Eye protection - recommended but not required for glyphosate, but required for triclopyr. You can double up by using safety glasses and a face shield.
An N95 mask or respirator for foliar spraying is not on all labels but is a very good idea.
How well do herbicides work?
Treatment of any invasive plant by any method is a multi-year proposition. With the most effective treatments, when you come back the next year, you can expect to see between 50% and 90% improvement, depending on how complete a response you got and how many plants you missed the first time (you will always miss some plants). After the original treatment, you’ll need to do about half as much work in subsequent years. Figure on three years of treatment for most invasive vines and five years for wisteria. After that, you will move into a maintenance phase of treating any stragglers and new arrivals from seeds are either carried in or that were lying dormant in the seed bank.
Training opportunities
Professional licensing
Volunteers in Virginia can become registered technicians or certified pesticide applicators (CPA), but it is extraordinarily difficult. The former requires onsite training for 20 hours by a CPA, studying the very long Core Manual, and passing a test. The latter requires an additional year of supervision by a CPA and passing another test. After that, continuing education training is required to renew the license. (The Core Manual is worth buying for yourself anyway because of all the extra details provided. It is not available online.)
High-level certificate course on terrestrial invasive plant management
The North America Invasive Species Management Association (NAISMA) offers an online course that takes approximately 20 hours to complete.
Training for volunteers by local jurisdictions
Local jurisdictions in Virginia are permitted to train volunteers to work under supervision on the land owned by that jurisdiction. Fairfax County and the Town of Vienna have programs for that. See the video for the online part of the Fairfax training on cut-stump treatment.