
Weed Control
How to Kill Bermuda Grass in a Fescue Lawn: Mow It Out First
Virginia Tech: tall fescue can completely kill bermudagrass at a 4-inch mowing height with no herbicide. Mow lower and no product will save you.

Selective Turf Herbicide (mesotrione, HPPD inhibitor)
★★★★★ 4.6/5
our editor rating how we score4.4/5 from 9,553 shoppers at Amazon — their number, not ours.
$55–$70
Typical price · 8 oz; label spot rate is one gallon of spray per 1,000 sq ft
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The mesotrione in Virginia Tech's bermudagrass programme, and the product whose label names Turflon Ester as its tank-mix partner.
The original Tenacity rather than a generic, and worth the distinction because the label is the one the extension programmes were written around. EPA Reg. 100-1267, mesotrione, Group 27 — an HPPD inhibitor, which is why treated plants bleach white before they die. Virginia Tech's selective bermudagrass programme for tall fescue pairs it with a turf triclopyr at three-week intervals, and Tenacity's own label references Turflon Ester by registration number, so the pairing is not an invention. Be precise about what the label does and does not say. It does NOT carry a bermudagrass-suppression-in-fescue use section. What it carries is a precaution: bermudagrass, along with bentgrass, Poa annua, kikuyugrass, zoysiagrass and seashore paspalum, is sensitive to Tenacity, and the label says to avoid spraying those turf types unless control and/or injury can be tolerated. That clause is the basis the programme rests on. It also caps perennial ryegrass and fine fescue at 5 fl oz per acre, and the bleaching is dramatic enough that people think something has gone wrong the first time.
Product type
Selective Turf Herbicide (mesotrione, HPPD inhibitor)
Active ingredient
Mesotrione, suspension concentrate (4 lb per gallon)
Price range
$55–$70
Coverage
8 oz; label spot rate is one gallon of spray per 1,000 sq ft
Best for
Cool-season lawns where mesotrione's own weed list matters, and as the extension programme's partner for bermudagrass suppression
our editor rating
4.6 out of 5
Label read on EPA's label database
EPA Reg. No. 100-1267
We opened this product's accepted label on EPA's own Pesticide Product Label System — the strongest source available for what a product is registered to do.
Full label read 2026-08-03 on EPA PPLS (accepted 2022-09-28). 'Tenacity', EPA Reg. 100-1267, mesotrione, Group 27. Checked specifically for the bermudagrass-in-fescue use because Virginia Tech's programme uses it: the label does NOT contain that use section. What it contains is a USE PRECAUTION — 'Bentgrass, Poa annua, kikuyugrass, zoysiagrass, seashore paspalum and bermudagrass are sensitive to Tenacity applications. Avoid spraying these turf types unless control and/or injury can be tolerated.' That is the clause the extension programme relies on, and this record says so rather than implying a labelled use. The label also has a 'Dormant bermudagrass applications only' section at 5 fl oz/A for winter weeds, a Florida-only goosegrass mixture, and a cap of 5 fl oz/A on perennial ryegrass and fine fescue. It references Turflon Ester (triclopyr, EPA Reg. 62719-258) and Barricade 65WG (prodiamine, EPA Reg. 100-834) by number.
Where this page and the container disagree, the container wins — the label is the legal authority on rates and restrictions. How to read one yourself.
Matched against each state's actual disease, weed and pest pressure.
Application window: April–May and September, and check every label against centipede before it leaves the shelf
Application window: June through July, inside the same short window everything else happens in. There is no autumn second chance
Application window: March–May and during monsoon flushes; Celsius-type products handle 100°F+ windows
Application window: Bounded by the label's temperature ceiling rather than the calendar — spring treatments finish before the June heat arrives, and nothing selective goes down again until September cools off
Application window: March–May while weeds are young; avoid spraying drought-stressed turf in summer
Application window: May–June and September; high-altitude sun makes stressed turf easy to injure, so spot-treat rather than blanket-spray
Application window: Broadleaf sprays in May–June and again in September, when the weeds are moving sugars to the roots; skip July and August, when a stressed cool-season lawn takes the injury and the weed does not
Application window: April to late May, then September into October. Skip July and August entirely: this is the transition zone, and a stressed tall fescue lawn takes the injury the weed shrugs off
Application window: March–May and October–November; avoid applications above 85°F
Application window: April to early June and September–October; avoid mid-summer sprays on stressed turf
Application window: Year-round where the turf is actively growing, which is most of the time; the constraint is heat and drought stress on the leeward side rather than a dormant season
Application window: Late April into June, then September into October; skip the July and early August heat, which is also when UI's own fertilizer schedule goes quiet
Application window: May–June and September; fall beats creeping charlie best
Application window: October is the most effective month for broadleaf weeds; never apply above 80°F or to drought-stressed turf
Application window: October, and October is most of it — but check the wind and the date against what is happening in the fields, because early-summer growth-regulator drift is a real seasonal risk here and your own spray carries the same way
Application window: April into May and again in September–October; avoid July and August, when a tall fescue lawn here is already at its limit
Application window: April–May and September–October; autumn is the knockout window for the wild garlic that defines a Kentucky winter lawn
Application window: June, then a narrow late-August to mid-September window. Maine's usable autumn is the shortest in New England
Application window: April–May and September–October; autumn is the knockout window for the ground ivy and violet the Piedmont is full of
Application window: A narrow autumn is the real window here: late September into October, after the summer heat and before New England's early frost closes the season
Application window: May–June and September; autumn is the stronger window for perennial broadleaf weeds
Application window: Late May–June and September; autumn is the stronger window for perennial broadleaf weeds
Application window: April–May and September, avoiding the midsummer heat restrictions on most labels
Application window: April–May and September–October; skip summer sprays on drought-stressed fescue
Application window: June, then late August into September. In a sub-100-day valley there is no third chance
Application window: Late spring and again from late August through September, when perennial broadleaf weeds are moving reserves to the root
Application window: March–April and October in the south; May and September in the north
Application window: Late May into June, then late August through September. The autumn window closes earlier here than anywhere else in southern New England
Application window: May and September–October; autumn is the knockout window for perennial broadleaf weeds
Application window: Spring and early autumn; in the south skip the June heat entirely, and in the north the usable autumn window closes by early October
Application window: May and September–October; autumn is the knockout window for perennial broadleaf weeds
Application window: April–May and September–October; avoid spraying heat-stressed fescue in July–August
Application window: Early to mid-June, then late August into early September. There is no third opportunity
Application window: May–June and September; fall applications hit dandelion taproots hardest
Application window: Judged by wind before season: sustained wind is Oklahoma's normal condition, so the usable spray days are calm mornings in April, May and September rather than whole months
Application window: March–May and September–October; the long mild shoulder seasons give more usable spray days than most states get
Application window: May and September — fall is the knockout window for perennial broadleaf weeds
Application window: Broadleaf work in May–June and again in September; the September pass is the one that holds, because the weed is moving reserves down
Application window: April–May and September–October, and never above 90°F — centipedegrass is sensitive to 2,4-D both at spring green-up and in summer heat
Application window: Early to mid-June, then late August into September, which is the pass that actually holds on perennial broadleaf weeds
Application window: April–May and September–October; skip sprays on drought-stressed summer fescue
Application window: April–early June and September–October; avoid herbicides above 90°F
Application window: May and September, avoiding the intense midsummer heat on the label
Application window: Late May through June, then a short late-August to mid-September window. Vermont's autumn window is the narrowest in New England
Application window: April–May and September–October; skip sprays on heat-stressed fescue in July and August
Application window: April–May and September–October; WSU caps applications at 80°F, stricter than the 85–90°F ceilings used elsewhere
Application window: April into May and again in September–October. Skip July and August: this is transition-zone country and a heat-stressed tall fescue lawn absorbs the injury the weed does not
Application window: Early to mid-fall is the favourable window for dandelion and other perennial broadleaf weeds
Application window: June, then late August into September. UW's own framing is useful: a slow-release application covers a 90 to 100 day growing season, which is roughly the entire Wyoming season
Common questions
Syngenta Tenacity Turf Herbicide, 8 oz typically runs $55–$70, covering 8 oz; label spot rate is one gallon of spray per 1,000 sq ft.
Syngenta Tenacity Turf Herbicide, 8 oz targets bermudagrass (as a sensitive species), crabgrass, nimblewill, creeping bentgrass.
Mesotrione, suspension concentrate (4 lb per gallon), registered under EPA Reg. No. 100-1267.
Bermudagrass suppression in fescue is NOT a labelled use section — the label frames bermudagrass as a sensitive species instead
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