Weeds in North Texas don’t take a season off, but they do change on you. The henbit smothering your beds in February is a completely different animal from the spurge taking over in July. Fighting weeds reactively — only dealing with them when you see them — is an endless game you can’t win. A seasonal weed control schedule flips the script: you stay ahead of the waves instead of chasing them. Here’s exactly what to do and when, tailored for Arlington’s climate and our specific weed pressure. If you’d rather hand this off, our flower-bed weed control service follows this schedule for you all year long.
Winter (December – February): Set the Foundation
North Texas winters are mild enough that cool-season weeds keep pushing even in January. This window is critical for setting up your beds for the entire year.
- January – early February pre-emergent application: Apply a pre-emergent herbicide (prodiamine or dithiopyr work well in beds) before soil temperatures consistently hit 50°F. This targets henbit, chickweed, annual bluegrass, and other cool-season germinators. If you miss this window, those weeds are already on their way up.
- Hand-pull existing cool-season weeds: Any weeds already growing won’t be stopped by a pre-emergent — that only prevents new germination. Pull what’s there now, roots and all, while the soil is moist from winter rains.
- Refresh mulch: If your mulch has compressed below two inches, top it off. Three inches of hardwood or cedar mulch going into spring is your best passive weed suppressor. It also regulates soil moisture heading into the dry months ahead.
Spring (March – May): The Busiest Weed Month of the Year
Spring is peak weed season in Arlington. As soil temps climb through the 50s and into the 60s, everything germinates at once. Miss this window and you’re playing catch-up all summer.
- Early March — second pre-emergent application: Before soil temps consistently hit 55°F, apply a warm-season pre-emergent. This targets crabgrass, spurge, oxalis, and summer annual broadleaf weeds. Timing this application is the single highest-leverage weed control action of the year.
- Spot-treat what breaks through: Pre-emergents aren’t 100% — some weeds escape through mulch gaps, soil disturbance, or missed edges. Use a selective post-emergent or targeted glyphosate application on stragglers. Don’t broadcast spray near ornamentals.
- Watch for nutsedge: Nutsedge (nutgrass) starts poking up in April and May in wet or irrigated beds. It’s not a true grass, and most pre-emergents don’t stop it. A sulfentrazone or halosulfuron product applied when it’s young (three to five leaves) is far more effective than waiting until it’s established.
- Edge your beds: A crisp edge along lawn-to-bed transitions physically blocks Bermuda grass and other turf from creeping into the bed. Clean edges also make chemical spot treatments much easier and safer.
Summer (June – August): Manage Heat and Humidity Pressure
Arlington summers are brutal — triple digits by July — and some weed treatments don’t perform as well in the heat. But weeds absolutely don’t slow down.
- Monitor for spurge and pigweed: These warm-season annuals explode in summer heat and produce enormous amounts of seed before dying. The goal is preventing them from going to seed. Pull or spot-treat early and often.
- Watch Bermuda grass encroachment: Bermuda spreads aggressively via stolons in summer. Where turf is creeping into beds, a grass-selective herbicide (fluazifop or sethoxydim) applied directly to the invading runners is extremely effective and safe around most ornamentals.
- Avoid heat-volatile herbicide formulations: On days above 90°F, certain ester herbicide formulations volatilize and drift as vapor, potentially damaging nearby plants. Stick to amine formulations in summer, apply in the morning, and avoid windy days.
- Mulch management: Summer heat breaks down organic mulch faster. Check depth mid-summer and refresh if needed. A good mulch layer reduces soil temperature, conserves moisture, and keeps weed seed from making soil contact.
Fall (September – November): Set Up for Winter
Fall is the second-most important window for pre-emergent application. Cool-season weeds germinate as soil temps drop back below 70°F in October, and hitting them with a pre-emergent in September stops the whole cool-season flush before it starts.
- September pre-emergent application: This is your third pre-emergent of the year. Timing it before the first cool front keeps henbit, chickweed, and annual bluegrass from ever showing up in your beds this winter.
- Clean out summer annuals: Remove spent summer annual weeds before they drop seed. Spurge, in particular, drops seed prolifically, and every plant you remove now is hundreds of weeds you won’t have to fight next spring.
- Prepare beds for winter color: If you’re planting pansies or snapdragons for the winter season, do that after your pre-emergent has been watered in and has had a few days to set. Digging and transplanting after application breaks the pre-emergent barrier only in the disturbed areas, not the whole bed.
Year-Round Habits That Keep Beds Cleaner
The schedule above does most of the heavy lifting, but a few ongoing habits make it even more effective:
- Never let weeds go to seed. One spurge plant can drop 3,000 seeds. Remove weeds before they flower.
- Water deeply but infrequently. Shallow frequent irrigation keeps the top inch of soil moist, which is exactly where weed seeds want to germinate.
- Keep bed edges crisp to block turf encroachment year-round.
- Log your application dates so you’re not guessing when the pre-emergent needs refreshing.
For more on protecting specific ornamentals, see our post on safe weed control for flower beds around shrubs and ornamentals.
Is a Three-Application Pre-Emergent Schedule Really Necessary?
In most of the country, two applications (spring and fall) is the standard. But Arlington sits in a climate zone where we get both cool-season and warm-season weed pressure, our winters are mild enough that cool-season weeds can germinaste in January, and our springs arrive fast. Three targeted applications — late January, early March, and September — gives you consistent coverage across all three weed seasons. Skip one and you’ll notice the gap.