If March is when you prepare for spring in North Texas, April is when spring arrives—fast, warm, and full of competing demands on your lawn. Grass breaks dormancy, roots begin actively growing, and the DFW sun starts putting in the long, intense hours that will define the season. But the weeds wake up with equal enthusiasm, and April’s specific combination of warming soil, mild air temperatures, and rising soil moisture creates the most important window of the year for broadleaf weed control. Miss it, and many of the most troublesome weeds in the region will set seed, establish deep roots, or transition into summer survival mode before you can reach them.
Why April Is the Most Important Month for Broadleaf Weed Control
Post-emergent broadleaf herbicides are most effective when applied within a specific temperature range—generally 50–85°F air temperature at the time of application, with the target weeds actively growing. April in Arlington and the surrounding DFW suburbs delivers this combination consistently. Daytime highs in the 65–80°F range are typical, soil is warming rapidly, and the cool-season broadleaf weeds that have been building through late winter are approaching peak size.
That size matters. A dandelion or clover plant that has been growing since January is large enough to absorb and translocate a herbicide dose down to its root system effectively. The same product applied to a small seedling in January would contact less leaf surface and deliver far less herbicide to the roots. April hits the sweet spot: plants are big enough to treat effectively, temperatures are in the ideal range for uptake, and the weeds haven’t yet had time to set seed and spread to new areas of the lawn.
Once May arrives and temperatures regularly push into the 90s, many cool-season broadleaf weeds go semi-dormant or die back naturally from heat stress. Applying herbicide to a heat-stressed plant is far less effective—the plant isn’t actively metabolizing, so it can’t move the chemistry where it needs to go. April is the window. After that, you’re waiting until fall.
Common April Weeds in DFW Lawns
April’s weed pressure in North Texas is diverse. The species that dominate Arlington lawns in early spring include:
- Dandelion — Deep taproot, yellow flowers turning to seed heads rapidly in warming temperatures. One mature plant can disperse hundreds of seeds before it dies back.
- White clover — Spreads aggressively by stolons in addition to seed. Low-growing and difficult to mow out, particularly in St. Augustine.
- Oxalis (wood sorrel) — Yellow-flowered, clover-like appearance. Notably resistant to some standard three-way herbicide formulations—product selection matters with this one.
- Thistle — Deep taproot, spiny leaves, and significant seed production if allowed to flower. April is the window to treat before it bolts.
- Wild violet — Notoriously difficult to control, particularly in shaded areas. Requires a product with triclopyr for reliable results; standard 2,4-D-based formulas are ineffective.
- Spurge (early) — Begins germinating in late March and April as soil temps cross 60°F. Spreading, mat-forming growth habit. Easier to control as a seedling than a mature plant.
Identifying which species are present determines which products and techniques will work. Blanket applications of a single chemistry fail on weeds like wild violet and oxalis that require specific active ingredients. This is one reason professional diagnosis before treatment makes a practical difference in outcomes.
How Post-Emergent Timing Works on Warm Soil
Post-emergent herbicides enter the plant primarily through the leaves, then move through the vascular system to the roots. For that translocation to happen effectively, the plant must be actively growing—which means active photosynthesis, open stomata, and a functioning root-to-shoot water flow. Warm soil accelerates all of these processes. In April, with soil temperatures at the two-inch depth rising through the 60–70°F range across DFW, broadleaf weeds are in peak metabolic activity.
For best results, apply post-emergent broadleaf herbicides when temperatures will remain above 60°F for at least four hours after treatment, with no rain expected for 24 hours, and no irrigation for 48 hours. Wind speed should be low enough to prevent drift. April mornings in Arlington frequently meet all of these conditions. Avoid application when a cold front is moving through—a temperature drop after treatment shuts down plant metabolism and dramatically reduces herbicide translocation.
Spring Fertilizer Timing for Bermuda and St. Augustine
April is also the month when spring fertilizer timing becomes a real decision. Bermuda grass in North Texas typically shows 50% or greater green-up by mid-to-late April in most years, which is the standard threshold for the first nitrogen application. St. Augustine follows a similar timeline, often a week or two behind Bermuda depending on exposure and location.
A properly timed spring nitrogen application in late April fuels the root development and canopy density that helps turf compete against summer weeds. However, the timing has to follow green-up—not the calendar. Applying nitrogen before the lawn is actively growing pushes leafy top growth that the root system can’t support, creates flush growth that is more susceptible to disease, and feeds any remaining cool-season weeds that are still present. Patience in April pays off in July and August, when a dense, well-fed Bermuda or St. Augustine canopy naturally suppresses weed establishment through shade competition.
The Risk of Fertilizing Too Early
Early-season nitrogen is one of the most common fertilizer mistakes on DFW lawns. Homeowners see the first green blush of Bermuda in early April—often 10–20% green-up—and reach for the fertilizer bag. At that stage, the root system is not yet ready for a full nitrogen load. The resulting top growth is weak, elongated, and pale, and it comes at the cost of root energy reserves that would have been better spent building the root system through April before pushing leaf growth.
Perhaps more critically in the context of weed control: early nitrogen strongly favors annual grassy weeds. Crabgrass seedlings that germinated in March love nitrogen as much as your Bermuda does. Applying nitrogen before your pre-emergent has had time to establish its barrier—or after that barrier has been compromised by early application timing—accelerates exactly the weed growth you’re trying to prevent. Let the lawn reach meaningful green-up before feeding, and time fertilization as a complement to weed control, not in competition with it.
Pre-Emergent Breakdown: What April Means for Your Spring Barrier
The pre-emergent applied in February or March begins losing effectiveness as spring progresses. Most granular pre-emergent products have an eight-to-twelve-week residual window under normal conditions, though heavy rainfall, irrigation, and warm soil temperatures all accelerate breakdown. A product applied in late February in Arlington may be losing effectiveness by late April or early May—exactly when late-germinating crabgrass, spurge, and other summer annuals are still emerging from the seed bank.
This is why many North Texas lawn care programs include a split-rate pre-emergent strategy: a first application in February or early March targeting the primary crabgrass germination window, and a follow-up application in late April or early May at a lower rate to extend residual coverage through the peak of summer annual germination. Relying on a single March application and assuming full-season coverage is a common source of mid-summer weed surprises in DFW lawns.
Nutsedge Watch Begins in April
Nutsedge is not a broadleaf weed and not a grass—it’s a sedge, and it operates on its own schedule. In North Texas, yellow nutsedge typically begins showing its first flush of above-ground growth in April as soil temperatures approach 65–70°F. You’ll recognize it as a rapidly growing, yellow-green triangular-stemmed plant that outpaces your mow height noticeably faster than surrounding turf.
April is actually the best time to begin nutsedge treatment. Plants are small, they haven’t yet produced underground nutlets, and the early-season applications of halosulfuron or sulfentrazone have maximum impact when the plant is still in the establishment phase. Waiting until June to address nutsedge that appeared in April means the plant has had two months to produce nutlets, each of which will generate a new plant next season. Starting treatment in April with appropriate follow-up applications three to four weeks later breaks the nutlet production cycle before it gets going.
Hamann’s Integrated April Approach
April is the month where everything happens at once, and sequencing matters. Our approach for Arlington and DFW lawns in April runs broadleaf post-emergent treatments first, while temperatures are still in the ideal spray range and before weeds set seed. Nutsedge monitoring begins in early April, with first treatments applied as soon as plants are confirmed present and actively growing. Fertilizer is held until green-up confirms the turf is ready, typically mid-to-late April for Bermuda. Pre-emergent status is evaluated to determine whether a follow-up application is warranted to extend residual coverage into the summer window.
For lawns on our full-season weed control and fertilizer services program, April treatments are sequenced automatically within the annual visit schedule. If you missed the March pre-emergent window and want to understand what options remain, see our post on March lawn treatment timing for North Texas spring green-up for context on how the spring program builds across both months.
Don’t Let April Weeds Get Ahead of You
Hamann Lawn Care & Weed Control handles broadleaf spray, nutsedge treatment, and spring fertilizer timing for Arlington and DFW lawns—plus 50% off your first application.