Trumpet vine laughs at most weed killers. Its woody stems and aggressive root system turn standard sprays into temporary setbacks rather than permanent solutions. You need an herbicide with enough penetration to reach the root crown and stop regrowth for good.
I’m Mohammad Maruf — the founder and writer behind Gardening Beyond. I spend my time studying herbicide chemistry, comparing triclopyr concentrations, analyzing mode-of-action data, and reading aggregated owner feedback on what actually kills woody vines from the inside out.
After sorting through five of the most popular formulations on the market, I landed on the chemistry and user results that matter. This guide covers the best herbicide to kill trumpet vine, with real specs and honest trade-offs for each product.
How To Choose The Best Herbicide To Kill Trumpet Vine
Trumpet vine’s deep, woody root system makes it one of the toughest invasive vines to eradicate. A single herbicide application often fails if the active ingredient doesn’t translocate to the roots. Look for these three factors before buying.
Active Ingredient — Triclopyr vs Glyphosate
Triclopyr is the primary weapon against woody vines. It mimics auxin plant hormones, causing uncontrolled growth that kills broadleaf plants from the inside. Glyphosate works on foliage but often misses the root crown on trumpet vine. Most brush killers with triclopyr deliver far better long-term results on established trumpet vine infestations.
Application Method — Concentrate vs Ready-to-Use
Concentrates give you control over mixing ratios, which is critical for trumpet vine. A higher concentration applied to freshly cut stumps via paintbrush beats a diluted foliar spray every time. Ready-to-use formulas are convenient but typically lack the potency needed on thick, woody stems unless applied directly to a cut stump.
Surfactant Need
Trumpet vine leaves have a waxy cuticle that repels water-based sprays. Without a surfactant, droplets bead up and roll off before the herbicide can penetrate. Many concentrates require you to add a few drops of dish soap or a commercial surfactant to achieve proper leaf wetting and absorption.
Quick Comparison
On smaller screens, swipe sideways to see the full table.
| Model | Category | Best For | Key Spec | Amazon |
|---|---|---|---|---|
| Bonide Poison Ivy & Brush Killer BK-32 | Mid-Range | Lawn-safe root kill on trumpet vine | Triclopyr concentrate, 32 oz | Amazon |
| Monterey Brush and Vine Control | Premium | Complete root system kill | Triclopyr concentrate w/ measuring spoon | Amazon |
| Tordon RTU Brush Killer | Premium | Ready-to-use cut-stump treatment | Ready-to-use triclopyr, 32 oz | Amazon |
| Southern AG Brush Weed Killer | Mid-Range | Budget-friendly high-concentration triclopyr | Triclopyr concentrate, 32 oz | Amazon |
| Image Brush & Vine Killer Concentrate | Budget | Entry-level option needing surfactant | Imazapyr-based concentrate, 32 oz | Amazon |
In‑Depth Reviews
1. Bonide Poison Ivy & Brush Killer BK-32, 32 oz Concentrate
Bonide’s triclopyr concentrate hits the sweet spot between potency and lawn compatibility. Real buyer reports confirm it kills trumpet vine roots permanently when applied to hot, sunny leaves with 48 hours of dry weather. It targets over 240 weed types including poison ivy, kudzu, and wild blackberries, making it a versatile tool for anyone dealing with multiple invasive species.
The formulation is designed to spare bluegrass, fescue, rye, Bermuda, and zoysia lawns when applied correctly. For cut-stump treatment, you apply the concentrate undiluted with a paintbrush directly to the freshly cut stem — a method that delivers triclopyr straight into the vascular system of the trumpet vine. One verified buyer reported vines turning brown within a week and never regrowing.
On the downside, several users noted that it required three applications to fully eliminate deep-rooted oxalis, suggesting trumpet vine may need a second pass on larger root systems. The chemical smell is strong, and proper PPE including gloves and an N-95 mask is non-negotiable. The 32-ounce bottle covers roughly 1,000 square feet at standard mixing ratios.
What works
- Kills trumpet vine roots without damaging lawn grasses
- Highly concentrated triclopyr for cut-stump or foliar use
- Reliable within one to two weeks on sunny days
What doesn’t
- Requires 48 rain-free hours for full absorption
- Strong chemical odor demands full protective gear
2. Monterey Brush and Vine Control Bundled with Measuring Spoon
Monterey’s concentrated triclopyr formula comes with a measuring spoon, which sounds minor until you realize how easy it is to under-mix. Reviews consistently call it the most effective vine and weed killer they’ve used, with one buyer saying it “killed everything” they applied it to, including invasive shrubs and poison ivy. The concentrate treats poison oak, alder, blackberry, cottonwood, and honeysuckle in addition to trumpet vine.
The cut-stump method is where this product shines. Apply undiluted directly to a freshly cut stump, and the triclopyr translocates to the root system within hours. One user reported that a second application on poison ivy finished the job completely, reinforcing that persistent trumpet vine may require a follow-up pass. The formula also prevents resprouting from the stump, saving you from repeated trimming.
The only hiccup is that a small number of buyers needed two applications to get full root kill on established vines. The 32-ounce bottle is a concentrate, so mixing yields multiple gallons of spray solution. Keep people and pets away until the spray dries, and avoid drift onto edible plants — this is a non-selective herbicide designed for non-crop areas only.
What works
- Includes a measuring spoon for precise mixing
- Excellent translocation to root system via cut-stump
- High concentration treats large areas with small bottle
What doesn’t
- May need a second application on large trumpet vine roots
- Not safe for use near edible crops or desirable plants
3. Tordon RTU Brush Killer, Ready to Use, 32 oz
Tordon RTU is a ready-to-use triclopyr formula that many experienced landowners call the only thing that works on woody vines. One reviewer described trumpet vine as a “hydra” and confirmed that Tordon killed the entire root system with a sparing application to a fresh cut stump. The ready-to-use format means no mixing — just apply within seconds of cutting the stem for maximum uptake.
Users recommend using a squeeze bottle or foam brush to apply the liquid directly to the outer ring of the cut stump, avoiding overspray on the ground. For small stems, a drip-and-spread method works. One buyer treated a mulberry weed tree that bled sap after cutting, yet the tree still died completely. Tordon also effectively killed invasive buckthorn and honeysuckle across multiple reports.
The clear trade-off is cost per application compared to concentrates. A single 32-ounce bottle won’t cover large-scale infestations as economically as a concentrate you mix yourself. The ready-to-use format also lacks the flexibility to adjust concentration for tougher vines. Wear nitrile gloves during application — the chemical is potent and can absorb through standard latex gloves.
What works
- No mixing required — apply directly to cut stump
- Extremely effective on woody vines and weed trees
- Kills the entire root system with one application
What doesn’t
- Higher cost per ounce compared to concentrates
- Not economical for large or dense vine patches
4. Southern AG 01113 Brush Weed Killer, 1 Quart (32 oz)
Southern AG packs a high concentration of triclopyr into a 32-ounce bottle at a price that undercuts most competitors. One buyer directly compared it to BioAdvanced, noting it delivers equal potency for less money. The formula is designed for non-crop areas like roadsides, rangeland, pastures, and fence lines where trumpet vine often takes hold.
Users report rapid results on most brush and vines, with one saying it killed weeds that had grown through weed block and rock after big-box store products failed. The concentrate covers 512 to 1,024 square feet per gallon when mixed according to label instructions. It also prevents sprouting on clean-cut stumps, making it a solid choice for cut-stump treatment on trumpet vine.
The downside is narrow effectiveness on certain woody species. One buyer noted it did nothing to strangler fig plaguing their tree, suggesting that some deeply rooted vines may require a different active ingredient or higher concentration. Southern AG is also primarily marketed for non-crop use — you won’t find lawn-safe claims like Bonide offers.
What works
- High triclopyr concentration at a low price per ounce
- Works on brush and vines where standard weed killers fail
- Prevents resprouting on cut stumps
What doesn’t
- Ineffective on some deeply-rooted woody species
- Not labeled for lawn-safe use
5. Image Brush & Vine Killer Concentrate, 32 oz
Image’s brush and vine killer uses imazapyr as its active ingredient instead of triclopyr, giving it a different mode of action that some users find effective on poison ivy and kudzu. The concentrate covers up to 4,000 square feet, making it the largest coverage option per bottle in this roundup. One verified buyer killed Himalayan blackberries across 2,000 square feet with a 4-ounce-per-gallon mix.
The critical catch is that Image requires a surfactant to work on waxy-leaved vines like trumpet vine. Multiple reviewers confirmed that adding a squirt of dish soap to the sprayer made the difference between failure and success. Without a surfactant, the spray beads up and rolls off the leaves. One buyer reported zero results after a full week, while others saw full browning within three weeks when they used the correct adjuvants.
Image is the most affordable option here, but it demands more user knowledge and preparation. Beginners who skip the surfactant step will likely be disappointed. For experienced gardeners willing to dial in the mix ratios and use a surfactant, it offers good coverage area per dollar. It is not lawn-safe, so avoid overspray on desirable turf.
What works
- Covers up to 4,000 square feet per bottle
- Kills tough weeds like kudzu and blackberry with proper mixing
- Budget-friendly price point
What doesn’t
- Requires added surfactant for waxy trumpet vine leaves
- Inconsistent results reported without correct mixing ratios
Hardware & Specs Guide
Triclopyr Concentration Matters
Triclopyr is the gold standard for woody vine control because it translocates to the root system and prevents regrowth. Concentrates typically range from 8% to 13% triclopyr by volume. Higher concentrations allow you to mix a stronger solution for cut-stump treatment or dilute more for large foliar sprays. Southern AG and Bonide both deliver high-concentration triclopyr at competitive prices.
Cut-Stump vs Foliar Application
Cut-stump treatment involves applying undiluted concentrate to the freshly cut surface of a trumpet vine stem within minutes of cutting. This method delivers the herbicide directly into the vascular system, bypassing waxy leaves and achieving nearly 100% root kill. Foliar spraying works but requires a surfactant and rain-free conditions. For established trumpet vine, cut-stump is the proven winner.
FAQ
What active ingredient kills trumpet vine roots permanently?
Can I spray trumpet vine leaves or should I use cut-stump method?
Do I need a surfactant for trumpet vine herbicide?
How long does it take for herbicide to kill trumpet vine?
Final Thoughts: The Verdict
For most gardeners, the herbicide to kill trumpet vine winner is the Bonide Poison Ivy & Brush Killer BK-32 because it combines high-concentration triclopyr with lawn-safe selectivity and reliable root kill in one application. If you want a ready-to-use cut-stump formula with no mixing, grab the Tordon RTU Brush Killer. And for a budget-friendly concentrate that cuts costs without cutting potency, nothing beats the Southern AG Brush Weed Killer.