Emerald Ash Borer Is Pushing South: How to Protect (or Replace) Your Ash Trees

If you’ve got Arizona ash, green ash, white ash, or any ash cultivar on your Houston property, take this one seriously. The emerald ash borer (EAB)—a small, metallic-green beetle that kills ash trees—has continued moving across Texas. In 2024 and 2025, Texas A&M agencies reported new county confirmations, including a July 2025 update noting five additional counties and the southernmost U.S. detection in Bell County. Translation: the risk line keeps sliding south toward more Gulf Coast communities.

Below is a practical guide to help you spot EAB early, decide when treatment is worth it (and when removal is the safer move), and what to replant if an ash is too far gone.

Quick refresher: what EAB does (and why it’s so destructive)

EAB larvae tunnel beneath the bark and carve S-shaped galleries that cut off water and nutrient flow. Even healthy ash decline quickly—often within 2–3 years of infestation. Telltale field signs include D-shaped exit holes, top-down canopy dieback, epicormic shoots (sprouts) on trunks/large limbs, bark splits exposing galleries, and heavy woodpecker activity.

Why Houston should pay attention now

• Confirmed spread in Texas (2024–2025): Texas A&M Forest Service and AgriLife reported additional counties confirmed in 2024 and 2025; the 2025 update marks EAB’s southernmost U.S. record to date. That’s a strong signal for Greater Houston to inventory ash and plan ahead.

• All ash species are hosts: EAB attacks all North American ash—even otherwise vigorous trees—so “it looks healthy” isn’t a defense.

Spotting EAB: a homeowner checklist

Walk your ash in good light and look for:

• Top-down thinning and deadwood starting in the upper crown.

• Small, D-shaped exit holes (~⅛") in the bark.

• S-shaped galleries under flaking bark or at natural cracks/splits.

• Epicormic sprouts along the trunk or large limbs.

• Woodpecker flecking (fresh light patches where birds have fed).

If you see two or more of the above—or you’re in a neighborhood with suspected EAB—book a Tree Pest Control inspection before summer heat settles in.

Treat or remove? A simple decision framework

Best candidates for treatment generally include:

• High-value ash in good/very good condition (minimal canopy loss).

• DBH (trunk diameter at 4.5 ft) within the effective range for labeled products.

• Trees that can be safely and repeatedly accessed for injections.

When removal is safer/wiser:

• >30–40% canopy decline already visible.

• Structural issues (decay, big dead leaders) raise failure risk.

• Budget or site logistics make repeat treatments impractical.

• Tree is poorly sited (utilities, foundations) or conflicts with future plans.

Your Trees Over Houston arborist will confirm species (only ash are treated for EAB), measure DBH, rate canopy condition, and factor in neighborhood risk before recommending a path. (See our Tree Health Assessment service.)

What actually works: trunk injections (and timing)

For eligible trees, professional trunk injections are the gold-standard preventive/suppressive tool. University and Texas A&M guidance show emamectin benzoate injections can deliver multi-year protection (often ~2–3 years) when applied to appropriate-sized trees and on the right cycle. Expect re-treatment at labeled intervals.

How it’s done (high level):

1. An arborist calculates dose from DBH and product label.

2. Injection ports are installed at the root flare; the tree takes up material (transpiration-dependent).

3. Plugs are set; ports close; the product moves systemically.

Because uptake depends on active water movement, injections are scheduled when trees are leafed-out and transpiring—your arborist will pick the local timing window.

Real talk: Injections protect or suppress—they’re not a cure for a severely declining ash. If the canopy is already crashing, removal may be the safer call.

If removal is the call, do it safely—and finish the job

Once an ash is structurally compromised, branches can fail without warning. If removal is recommended, we’ll sequence:

• Tree Removal with proper rigging and drop-zone control.

• Stump Grinding to eliminate trip hazards, terminate sprouts, and prep the spot for replanting.

We’ll also handle debris disposal with sanitation in mind. (Ask about neighborhood coordination if multiple ash are being taken down at once.)

Replanting picks for Houston (not ash!)

Ready to pivot to species that love our soils and humidity? Consider these Houston-friendly options commonly used by local forestry groups and city lists; they offer shade, storm resilience, or seasonal interest—minus the ash-specific risk:

• Southern live oak (Quercus virginiana) – iconic Gulf Coast shade.

• Bald cypress (Taxodium distichum) – handles wet sites and heat.

• Cedar elm (Ulmus crassifolia) – tough, adaptable urban performer.

• Shumard oak / Nuttall oak (Quercus shumardii, Q. texana) – fast, strong structure with fall color.

• Mexican sycamore (Platanus mexicana) – big shade, drought-tolerant once established.

• Southern magnolia (Magnolia grandiflora) – evergreen canopy and blooms.

(Use the Texas Tree Selector to match species to your exact site and soil.)

Homeowner playbook: next 60–90 days

1. Book a Tree Pest Control inspection. We’ll confirm species, look for EAB signs, and rate canopy health.

2. Decide quickly: If the tree is a candidate, get on the Tree Injections schedule for seasonally correct timing; if not, plan safe removal before hurricane-season winds test weak wood.

3. Plan your replant now so you’re not caught treeless later—pick a species suited to your soil, sun, and space.

FAQs

How fast can EAB kill an ash?

Once infested, many ash die within 2–3 years as galleries choke off the tree’s plumbing.

Will one injection save a big, sick ash?

Probably not. Emamectin benzoate works best preventively or in early decline and usually needs repeating every 2–3 years per label and research. Heavily declining trees are usually removal candidates.

Can I treat it myself?

EAB injections are licensed, label-restricted procedures that require the right equipment, dose math, and timing. DIY soil drenches aren’t equivalent and can risk off-target impacts. Schedule a pro.

Should my neighbors worry?

Yes—EAB management is most effective when neighbors coordinate monitoring and decisions. Ask us about HOA or block-level assessments and treatment days.

How Trees Over Houston can help (CTAs/Links)

• Tree Pest Control → Inspection & diagnosis for suspected EAB (species check, canopy rating, gallery/exit-hole confirmation).

• Tree Injections → Emamectin benzoate programs for eligible ash, planned on the right seasonal uptake window and cycle.

• Tree Removal → Safe takedowns of compromised ash, with traffic/property protection and debris handling.

• Stump Grinding → Clean finish and site prep for replanting.

Need replanting ideas tailored to your block? We’ll match species from local lists and the Texas Tree Selector to your soil, irrigation, and shade goals.