5 Best Herbicide for Morning Glory | Twist, Squeeze, Kill

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A three-weed blend that treats your whole yard without tearing up the turf.

Here is the case where 32 fluid ounces stretches a long way: this bottle is listed for 5,000 sq ft, which is a genuine whole-yard figure rather than a spot-treatment one. The formula is a patented combination of three proven weed killers, sold as Trimec, and the label names 9 turf types it is cleared for. If your morning glory has crept into the lawn itself rather than up a fence, this is the class of product you want — it targets the weed, not the grass around it.

The label suggests pairing it with a surfactant for increased performance, which is a small extra step that helps the spray cling to waxy leaves instead of beading off. Directions cover both conventional and hose-end sprayers, so a basic end-of-hose bottle works. Buyers report good results mixing at 2 oz per gallon, avoiding rain for 24 hours, and spraying young weeds rather than mature ones — and that last point is the honest limit here. Trimec-type formulas do their best work on weeds that are still growing.

What you have to plan around is return visits. Several users describe strong knockdown followed by weeds coming back within a few weeks, which points to the lack of long-season residual control rather than a weak mix. Treat this as one tool in a rotation, not a one-and-done season killer. Grass damage is possible if you spray the entire yard rather than spot-treating, so be deliberate about where the nozzle points.

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Built for cool-season grass, with a two-week clock you have to accept.

Cool-season lawns need a different formula, and this bottle says so on the label. It is listed for Northern grasses including Kentucky Bluegrass, Perennial Ryegrass, Fescue spp. including Tall, Red, and Fine Leaf Fescues, and Zoysiagrass. If you live in a cool-season climate and your morning glory has moved into the turf, check that grass list first — spraying a formula meant for the wrong turf type is how people damage a lawn they were trying to save.

The scope here is broad: the label states it kills 253 types of weeds as listed, covering crabgrass, dandelion, clover, yellow nutsedge, poison ivy, chickweed, oxalis, and purslane, with up to 3 month weed control as listed. It is rainproof in 3 hours, and the 32 fluid ounce concentrate covers 5,000 sq ft, matching the Southern Ag Trimec bottle on ground treated per bottle. Mix it in a tank sprayer or a Dial ‘N Spray and apply evenly.

Expect a slow burn on speed, though. It starts working immediately per the label, but visible change often takes about two weeks on the tougher targets, and crabgrass is the recurring weak spot — owners mention it shrugging off a first pass and needing a heavier, well-saturated second application with a pump sprayer before it finally gave. Overspray is the other risk: keep it off windy days because desirable plants in flower beds are vulnerable. Judge this one on the grass list and the coverage, not on instant gratification.

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Imazaquin concentrate labeled for vines, brush, and stumps — not turf.

This is the closest match on the list to what a morning glory problem actually is. The label names tough weeds, grasses, vines, brush and stumps including poison ivy, poison oak, poison sumac, wild blackberry and other listed plants, and states it kills roots and all with no regrowth from the roots. The active ingredient is ammonium salt of imazaquin, and one 32 fluid ounce bottle is listed for 4,000 square feet.

Weight tells you something practical too — at 2 pounds it is lighter than the Spectracide bottle at 2.5 pounds, so it is easier to haul along a fence line or up a slope in a backpack sprayer. Speed is where you must be patient. Users describe yellowing starting around 10+ days at a 4 oz per gallon mix, with most leaves yellow by three weeks, and a faster response at 5 oz per gallon going brown and dry by week four. Fall spraying is often recommended for woody vines, with results judged on spring regrowth.

Reviewers keep reporting the same thing: this kills plants that shrug off ordinary lawn weed killer — blackberry stands and poison ivy are the repeated examples. The reason is that the vine’s crown, not just its leaves, has to die. That also means it is not a lawn product and should not be broadcast over grass you want. Save it for blackberry and poison ivy that lawn formulas have already failed on.

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Triclopyr in a quart bottle, aimed at vines, brush, and cut stumps.

The active ingredient here is triclopyr (a vine-killing herbicide), and the label lays out its lane clearly: it kills vines and many hard to control plants, and prevents sprouting on clean-cut stumps. It is meant for non-crop areas like road sides, rangeland, pastures and fences. That fence and roadside framing is exactly where morning glory tends to win, and the stump clause is a useful extra — if you cut a woody vine back and then treat the fresh cut, you are attacking the part that keeps regenerating.

Coverage is quoted differently from the rest of this list: 512–1024 square feet per gallon, so you are measuring in mixed gallons rather than a single bottle figure. That makes the quart a concentrate you dilute and stretch, and the small bottle size is not the whole story. Customers note it working on pokeweed in about a week and taking blackberry bushes and cherry trees down within a week of a morning application before several full-sun days.

Where you need to slow down is the word “most.” Triclopyr is strong on the plants it is listed for, and a strangler fig is the named example where it did nothing. Woody plants with different physiology can simply ignore it. Overspray near desirable plants is the other caution — this is not a spot-and-forget spray. And as with any brush killer, the clock is slower than a contact herbicide, so judge it after a week, not an hour.