Herbicide Application Techniques & Tools

At the Driftless Prairies, we have found 4 very effective herbicide treatment application methods: Spritzing, Cut & Treat, Swiping, and Foliar Spraying. All of these are designed to minimize collateral damage and reduce the use of herbicide. Each has its own set of pros and cons. We use them in combination depending on the situation and our time.

Spritzing Method(s) 

One other technique we use a lot is called “Spritzing.” This method can used used on 1) cut stems, 2) on leaves as a foliar application, or 3) at the base of a stem as a basal application. We only use one herbicide mix when we “spritz,” too –Element 4 mixed with bark oil.

A foliar spritz can be done on 1-4 leaves rather that coating each that is required with aqueous foliar spraying. Spritzing can involve a full squeeze of the nozzle or a partial. I just love that it controls the amount of herbicide put out.

Pros: Fairly easy; uses less herbicide than foliar spraying

Cons: Expect some collateral damage; can be time consuming

When to do it: This would be done in spring or early summer when the resprouts were in the rosette stage. 

Handheld Sprayers for Spritzing

We tend to use this more than the backpack any more. We have managed the invasives sufficiently that we only have minimal spot spraying to do, a technique we call “spritzing.”

Which handheld you use is a preference. We have found the cheap ones from Ace Hardware (photo just to the right) to last longer and the expensive pump brands (photo on the far right). We also have more control over the amount of herbicide being put out, which is very important to minimize collateral damage and maintaining soil health.

Spray bottle
pumping handheld spray bottle

Cut & Treat Method

The Cut & Treat is used for management of woody resprouts or goldenrod mitigation. Sometimes it’s a Lop & Treat, it depends on the equipment we use. Lopping means we can cut more than one goldenrod stem or we can cut a large woody stem. It’s our definition and helps us communicate.

When lopping, we use the first 2 tools shown to the right. For cutting, we use a set of hand clippers.

For carrying the spray bottle of herbicide, we’ve drilled holes in a coffee can and zip tie it to the belt that carries our hand clippers. This keeps the spray bottle in a convenient location, leaving our hands free to lop. It also contains the herbicide should the bottle leak.

Pros: It’s thorough; it kills the stem; you know what’s been treated and what hasn’t; it puts out the least amount of herbicide; it has the least material & equipment costs; and it’s flexible on when you can do it

Con: it’s time consuming

When to do it: Can be done any time you have time but it’s easiest after a burn or in the winter when herbaceous plants are senesced.

loppers
A coffee can is an excellent way to carry a spray bottle

Swiping Method

This technique can be used in a couple of ways. We have successfully used it on small invasive woodies and brambles by swiping their stems in winter. You can successfully swipe stems that are brushcut to a heighth of 4-12″ tall or not cut at all. Whether you cut or not depends on your ability to traverse the woody area you need to manage.

We have also used the PVC herbicide pipe when we’re mitigating Tall goldenrod. Some areas of our land have enough diversity around the Tall goldenrod that mowing would create too much collateral damage. Yet, those places are too thick to efficiently use the lop and treat method. In these areas, with a brushcutter, we cut the stems to 8-12″ tall. Then we walk through with the PVC herbicide pipe and swipe the stems.

The PVC herbicide pipe is an inexpensive tool and needs to be part of your management toolbox. The Nature Conservancy has created a diagram and instructions for making this tool.

The herbicide we use is 20% trichlopyr mixed in bark oil blue. That is 64oz of trichlopyr to 2 gal of bark oil. This method will not work using herbicide mixed with water.

Pros: Fairly easy, less bending

Cons: May duplicate your efforts because you don’t know which as been done; requires purchase or construction of swiper

When to do it: This can be done at any time of the year. But….to reduce time, I’ve swiped in a year before I burned. Then after the burn, I would cut & treat whatever I missed.
OR
Wait until the next year, mow it and spray resprouts.

For Cut/Lop and treat of woodies stems, we cut the stem about 1/2″ from the ground, then spritz the cut end.

This is the most effective method for treating woodies.

The photo to the right shows the end of the cut stem. We use the cut & treat method on woodies after a burn when the stems are obvious. While they may be charred and appear dead, most are not.

The cut stem of a burned unwanted woody that isn't dead.

For goldenrod, you first begin by lopping the blooms off the plants. (See photo on left)

Once the blooms are lopped, you spritz the cut stems. (See photo on right)

In goldenrod clones as tight as this one (meaning there are no desired native plants inside the clone), you could give it a wider spray and save some time. We usually find desirable plants within so we focus on treating the cut end of each stem. 

Jim is lopping the blooms off the goldenrod
Jim herbiciding lopped goldenrod

When using this method for treating goldenrod, a few weeks later, this is what you want to see. You can also see the 2 stems that were missed (in the middle and along the right side). This photo clearly illustrates 2 things: 1) the importance of overseeding and 2) why it’s critical to have a multi-year plan. If you don’t overseed, those missed stems will have no competition and they could spread freely. Those missed stems are also the reason why dormant-season disturbance following this treatment can result in open space for untreated stems to thrive. It’s unreasonable to think stems won’t be missed, so having a multi-year plan is key.

Desired results of lop and treat on goldenrod

Foliar Spraying

When we foliar spray, we use the backpacks with our herbicide mixed with water. We use this technique when we’re walking a large area that has a large infestation of herbaceous invasives. As our restorations have matured and our work has succeeded, we tend to use the spritzing method rather than the backpacks. This is because we can control the amount of herbicide being put out much easier with the handheld spray bottle. No matter how much you adjust a backpack sprayer, it puts out more than the handheld.

These backpack sprayers are awesome when doing spot spraying over a large acreage. They allow you to walk the acres without having to refill often.

The cons to these sprayers is it is difficult to control how much herbicide it released. There are adjustments but it’s still more than a handheld spray bottle would put out.

They also need to be cleaned after each use if you’ve put herbicide that is mixed with bark oil in it. Even if you’re going out the next day to use the same herbicide! That oil deteriorates the rubber diaphragm.

Pros: Can be done with a backpack sprayer

Cons: Lots of collateral damage; uses more herbicide than necessary; may not always kill the target plant; requires purchase & maintenance of a backpack sprayer

When to do it: This would be done in spring or early summer when the resprouts were in the rosette stage. 

backpack sprayer

For more information on herbicides, check out these 2 links.