This guide was submitted to guide BELL NO! members as they control CBF using safe and effective herbicide techniques on their own properties. BELL NO! does not condone “guerilla” spraying on neighboring properties or park lands at this time.

You don’t need to guess, improvise, or rely on bad advice from big-box employees. These are the same chemicals and strategies Cole Yates uses as a Minnesota-licensed Commercial Pesticide Applicator to eradicate Bellflower at hundreds of properties.

What to Use

Spring & Fall: Triclopyr Ester

• Herbicide: Alligare Triclopyr 4 (butoxyethyl ESTER)

• Adjuvant: Methylated Seed Oil (MSO) – such as Southern Ag brand

• Water: Distilled water (especially important in areas with hard tap water)

• Label language regarding dosing for Alligare Triclopyr 4: “Do not exceed 1.5 oz per 1,000 sq ft (per gallon of water) in any single broadcast application”

Triclopyr ester is most effective during cool seasons when plants are either growing rapidly (spring) or pulling resources back to their roots (fall). Avoid the “amine” version sold at hardware stores: it’s less effective, more water-soluble, and more likely to wash off in rain. Triclopyr will not hurt established cool-season lawns when following label instructions.

Even in the summer, if you’re making your first application, start with triclopyr on a cool day. Triclopyr goes deep down into the mother tubers. If you begin with glyphosate, you’ll burn off the tops without getting the tubers two feet underground. Glyphosate shuts the plant down and prevents it from absorbing triclopyr. Triclopyr does not prevent the uptake of glyphosate.

Summer: Glyphosate

• Herbicide: Glyphosate - such as Compare-N-Save 41% glyphosate concentrate

• Adjuvant: Non-Ionic Surfactant – such as Southern Ag Spreader-Sticker

• Water: Distilled water

• Label language regarding dosing for Compare-N-Save 41% glyphosate concentrate: “use 2.5 oz (5 Tbsp) per gallon of water”

Apply glyphosate after at least one application of Triclopyr, preferably two. Triclopyr ester becomes volatile in heat, making it risky near ornamentals so you should avoid applying in temperatures above 75 degrees or so. Glyphosate doesn’t volatilize and actually performs better in high temperatures, making it a solid summer option. It should not be applied at temperatures above 85 degrees. You should know that glyphosate will kill turfgrass too, so use with precision.

Where to Buy

Order from DoMyOwn.org (online vendor that ships). BELL NO! is not affiliated with them, but our members have purchased numerous products from them. They carry the real versions of these products and store them properly and ship them safely to Minnesota. Avoid Amazon. Many herbicide products sold there are counterfeit, improperly labeled, or stored in unsafe conditions.

How to Mix (Both Products)

Always use distilled water. Most tap water in the Upper Midwest is alkaline and full of calcium, magnesium, and other ions that bind to herbicides and reduce their effectiveness. If you’re experienced with herbicide mixing, you may substitute distilled water with tap water that has been conditioned using spray-grade ammonium sulfate. However, distilled is simpler for most homeowners.

Mixing Order:

1. Add half your total water volume (distilled only).

2. Add herbicide concentrate at the max label rate.

3. Add your adjuvant:

   • Triclopyr: Add MSO (Southern Ag) at the max label rate

   • Glyphosate: Add Spreader-Sticker (non-ionic surfactant) at the max label rate.

4. Top off with the remaining water.

5. Shake or agitate again until fully combined.

Syringe Application: Small-Batch Precision

A 60 mL Luer Lock syringe with a Luer fine-tip applicator makes spot applications easy. No leaky brushes, no mess. It also works well to measure minute quantities of chemical in mL so you can mix up a small batch for spot treatments.

• Want to mix just 8 oz (1/16 gallon)?

• If your label calls for 1.5 oz/gallon, multiply:

  • 1.5 × (1/16) = 0.09375 oz ≈ 2.77 mL

Apply directly onto leaves with pinpoint control. Just be gentle…pulling the plunger too hard can cause it to burst. Always wear eye protection.

Tip: Oil-based products degrade rubber. Use a new syringe every few uses. The tips, however, can be cleaned and reused.

How to Treat Larger Areas

Use a 1-gallon pump sprayer with adjustable pressure. Light trigger pulls create dribbles; full pressure gives you a mist. You can adjust your tip to avoid a fine spray, minimizing drift risk.

• Spray only on calm, cool days (under 75°F and under 10 mph wind).

• Treat just the bellflower leaves, not the whole bed.

• Skip spraying near edibles, new transplants, or sensitive ornamentals.

• If needed, use the syringe method for precision spots.

PPE and Safety

Triclopyr and glyphosate have been classified as “practically nontoxic” to mammals and insects. However, triclopyr ester should be avoided in aquatic areas because it has some toxicity to water-dwelling species. BELL NO! recommends you contact a licensed applicator if you are attempting to manage a sensitive site.

Minimum PPE required:

• Chemical-resistant gloves (nitrile or neoprene—not latex)

• Long sleeves and pants

• Closed-toe shoes

• Tight-fitting safety goggles (not just sunglasses or glasses)

Wash up immediately after spraying before removing your gloves and then again after. Keep people and pets out of treated areas for at least 24 hours.

What We Don’t Recommend

• We don’t overapply. It’s not legal and high concentrations persist in the soil. Triclopyr and glyphosate work just fine at the maximum labeled dose!

• We don’t store mixed spray. Herbicides lose potency quickly once diluted.

• We don’t dig or pull during herbicide application years. Disturbing roots makes the plant harder to kill and cuts off our pathways to get herbicides down deep into the mother tubers.

• We don’t let CBF flower! Snip off the flower stalks: don’t disturb the roots…they are busy absorbing the herbicide!

Bonus: Pre-Emergent Protection

Creeping Bellflower seeds can stay viable for up to seven years. If you’ve cleared an area, consider using a pre-emergent herbicide like Prodiamine (such as Barricade 4FL) to prevent seed germination. Apply in spring or late fall before snow.

Obtaining Professional Help

Ensure that any applicator you hire is a licensed Commercial Pesticide Applicator in your state. They should be willing to show you their certificate of liability insurance. Avoid those who solicit cash payments: they probably aren’t paying their taxes and are unlikely to be following other laws and best practices. For those in the Twin Cities, Cole Yates’ BellflowerBeater.com focuses on integrated pest management with property scouting, Flower Finder services, and targeted spraying.

You can view a full list of Minnesota-licensed Commercial Pesticide Applicators on the Department of Agriculture’s website. Make sure anyone you hire knows what the bell they are dealing with!