Oak Wilt Alert: Why Houston Homeowners Shouldn’t Prune Oaks Feb–June

If you’ve got live oaks or red oaks on your property, timing matters—a lot. In Greater

Houston, the window from February through June is prime time for oak wilt to spread. Fresh pruning wounds act like beacons to tiny sap-feeding beetles that can carry oak wilt spores from infected trees to yours. That’s why Texas A&M Forest Service urges Texans to avoid pruning or wounding oaks during this period and to paint any oak wound immediately—year-round.

Below is a clear, practical guide to keep your oaks healthy, what warning signs to watch for, and how our certified team at Trees Over Houston can help—with Tree Health Assessments, Tree Injections, and Tree Trimming scheduled at the right time.

Why pruning Feb–June is risky

• Insect activity peaks: Sap beetles (Nitidulids) are highly active in late winter and spring and are attracted to fresh cuts. If they’ve contacted fungal mats from diseased red oaks, they can deliver spores to your pruning wounds.

• Fresh wounds = open doors: Any new cut (from pruning, mowing, construction nicks, even storm damage) can be an entry point. That’s why immediate wound paint is required any time of year.

Bottom line: If the work isn’t an emergency, wait until after June to prune. If you must prune for safety, seal the wound right away.

The right way to protect your oaks (Houston edition)

1) Press pause on pruning (Feb–June)

Unless there’s a safety hazard, reschedule live oak and red oak pruning for mid-summer or later. If you absolutely must cut, paint immediately—spray paint or brush-on wound dressing both create an effective barrier.

2) Paint every oak wound—no exceptions

Any time of year, seal cuts the moment they’re made: pruning cuts, storm breaks, mower/weed-whacker nicks, construction scrapes. Don’t wait minutes—do it immediately.

3) Be careful with firewood

Don’t store or move red oak firewood of unknown origin; it can harbor fungal mats that start new outbreaks.

4) Book a Tree Health Assessment

If you’re in or near an area with oak wilt or you’ve seen odd leaf symptoms, a professional assessment can prevent a small problem from becoming a big one. Our arborists evaluate signs, site history, root graft risks, nearby removals, and more (details below). Guidance from Texas A&M aligns with this proactive approach.

Early signs of oak wilt you can spot

Oak wilt doesn’t always look like drought. Watch for:

• Live oaks: Leaves show veinal necrosis—the veins turn brown while the tissue between them may stay green or yellow. You’ll often see rapid leaf drop and a carpet of leaves with browned veins under the canopy.

• Red oaks: Symptoms can be less distinct at first, but trees often decline fast after infection, especially from spring into early summer.

If you notice these patterns—especially Feb–June—don’t prune to “clean it up.” Call for an assessment first. 

What our arborists check (so you get the right plan)

During a Tree Health Assessment, your Trees Over Houston arborist will:

• Confirm symptoms: Differentiate oak wilt from drought, nutrient issues, leaf scorch, or root damage; document any veinal necrosis patterns in live oaks.

• Map proximity risks: Look for nearby suspect red oaks, fresh removals, stored firewood, and utility or construction damage that may have created unsealed wounds.

• Review timing/history: Note any pruning or storm damage that occurred in the high-risk window (Feb–June).

• Consider root-graft spread: In live oak stands, the disease often moves underground through connected roots, which changes the management plan.

• Recommend lab confirmation when needed: For ambiguous cases, we can coordinate diagnostic testing before major decisions.

• Build an integrated plan: Correct-timing Tree Trimming, immediate wound sealing, sanitation of tools, careful debris handling, and—when appropriate—Tree Injections (fungicide) and root disruption options.

Do fungicide injections help?

For certain high-value oaks, trunk injections with a systemic fungicide (commonly propiconazole) can protect uninfected trees in high-risk areas or suppress disease in early infections as part of a broader strategy. Injections are typically repeated on an interval and must be timed correctly relative to disease pressure and tree physiology. Your arborist will advise if your tree is a candidate and what interval makes sense.

Important: Injections do not stop the disease from moving through root grafts—they’re a tool, not a cure-all. That’s why timing, sanitation, and (when needed) root management still matter.

Safe trimming still matters—just do it at the right time

Healthy structure and airflow reduce storm failures and secondary pests—but schedule non-emergency Tree Trimming outside the high-risk window and sanitize tools between trees. If a limb splits during a storm in spring, we’ll make the smallest necessary cut, seal it immediately, and document the site for follow-up in summer.

Quick homeowner checklist (Feb–June)

• Don’t prune live or red oaks unless it’s an emergency.

• Paint every oak wound immediately—cuts, breaks, nicks, all of it.

• Avoid questionable firewood; don’t move red oak wood around.

• Watch leaves: look for veinal necrosis on live oaks or rapid decline in red oaks.

• Call for a Tree Health Assessment before you take action.

Why this matters right now

Texas A&M Forest Service issues annual reminders as we approach spring: avoid pruning oaks Feb–June and seal wounds immediately—because that’s when beetles and fungal spores are most likely to connect with fresh cuts. Houston’s climate only reinforces this seasonal risk.

How Trees Over Houston can help (CTAs/Links)

• Tree Health Assessment → Get a clear diagnosis and an integrated plan (timing, sanitation, monitoring, and next steps).

• Tree Injections → Strategic, properly timed injections for qualifying trees in at-risk areas.

• Tree Trimming → Structure-first pruning scheduled after the high-risk window, plus immediate wound sealing for any emergency cuts.

Ask us about neighborhood-wide coordination, too—oak wilt management is most effective when neighbors align on timing and best practices. 

FAQ

Can I prune my oak in April if it’s just a small branch?

Avoid it. Size doesn’t matter—any fresh wound can attract beetles. If it’s a hazard, make the minimal cut and paint it immediately, then schedule finishing cuts after June.

What kind of paint/wound dressing should I use?

Use any black paint (spray or brush-on) or commercial wound dressing. The key is speed—apply immediately after cutting.

My live oak’s leaves have brown veins—now what?

That’s a classic oak wilt flag called veinal necrosis. Stop pruning, document the canopy, and request a Tree Health Assessment.

Do injections cure oak wilt?

No cure—but injections can protect or suppress in specific cases when used with other measures. Your arborist will advise based on species, size, timing, and proximity to known infections.

Ready to protect your oaks?

Houston’s oak canopy is part of what makes our neighborhoods feel like home. If you’re seeing suspicious symptoms—or you’re planning work during the Feb–June window—let’s talk first. We’ll line up a Tree Health Assessment, schedule Tree Trimming for the right season, and discuss whether Tree Injections belong in your plan—all aligned with the latest guidance from Texas A&M Forest Service.