A healthy ash tree in your yard is quietly on a countdown right now. The emerald ash borer — a metallic-green beetle no bigger than a grain of rice — has spread across every corner of Maryland, and an untreated ash in Charles, Calvert, or St. Mary’s County will almost certainly be killed by it. Once that tree dies, the wood dries and turns brittle within a year or two, and a removal that would have cost $1,200 while the tree was sound can climb past $3,500 once a crane is the only safe way to take it down.
I’m Alex Wright, and I run the crews at 855TREEMAN. I’m a Maryland Licensed Tree Expert, LTE #2123, licensed through the Maryland Department of Natural Resources. You can read more about how our team is licensed and how we work. I’ve walked hundreds of Southern Maryland properties with dying ash trees, and the pattern is always the same: homeowners wait, hoping the tree bounces back, and it never does. It just gets more dangerous and more expensive to deal with.
This guide is the honest version of the conversation I have on-site every week. What the beetle is, how to spot it early, and — the part that actually matters — whether your specific ash tree should be treated or removed.
What the emerald ash borer is, and why every ash here is at risk
The emerald ash borer (EAB) is an invasive beetle from Asia, first found in the U.S. in 2002 and confirmed in Maryland shortly after. The adult beetle nibbles ash leaves and does little real harm. The damage comes from the larvae. They tunnel into the layer just under the bark and feed on the tissue that moves water and nutrients up the trunk. Enough larvae, and the tree is effectively girdled from the inside — it starves branch by branch.
Here’s the part homeowners miss. Maryland was under a federal EAB quarantine for years, which restricted moving ash wood and firewood between counties. That quarantine was lifted in 2021. It was not lifted because the threat ended — it was lifted because the beetle had already spread so widely that containment was pointless. Deregulation meant the war was lost, not won. Today, every untreated ash in Southern Maryland should be treated as a tree the beetle will find. The USDA APHIS emerald ash borer program tracks the ongoing spread, and Maryland is squarely inside it.
Ash is common here — green ash and white ash line streets, edge fields, and shade a lot of older yards in St. Mary’s and Calvert. If you don’t know whether you have an ash, that’s the first thing to nail down, because untreated ash is not a “wait and see” tree anymore.
How to spot EAB damage before it’s too late
By the time an ash looks obviously sick, the beetle has usually been in it for two or three years. Early detection is worth real money. Here’s what I look for, roughly in the order it shows up:
- Canopy thinning from the top down. EAB kills the upper crown first. If the top third of the tree is thinning, bare, or dropping leaves early while the lower branches look fine, that’s a classic EAB signature.
- D-shaped exit holes. When adult beetles emerge, they leave a distinctive D-shaped hole about 1/8 inch wide — flat on one side, curved on the other. No other common Maryland pest leaves that exact shape.
- S-shaped galleries under the bark. Peel back a piece of loose bark and you’ll find winding, S-shaped tunnels packed with sawdust-like frass. This is the smoking gun.
- Bark splitting. Vertical cracks in the bark form over old galleries as the tree reacts to the damage.
- Epicormic sprouting. Shoots pushing straight out of the trunk or lower limbs — the tree’s panic response as the upper canopy dies.
- Woodpecker “blonding.” Woodpeckers strip the outer bark to reach larvae, leaving pale, flecked patches. Heavy woodpecker activity on an ash is often the first thing a homeowner notices from the ground.
If you’re seeing two or more of these, don’t wait for the rest to appear.
The EAB lifecycle, and why timing your treatment matters
The reason timing matters is that treatment works on the beetle’s schedule, not yours. Adult beetles emerge from late May through July, mate, and lay eggs on the bark. Those eggs hatch, and the new larvae bore in and feed through late summer and fall, then overwinter under the bark before pupating in spring.
For treatment to protect a tree, the product needs to be in the tree’s tissue before and during the larval feeding window. In practice, that means the ideal treatment window in Southern Maryland is spring into early summer — generally mid-April through June — so the insecticide is fully moved through the canopy when the beetles are active. Miss that window and you often lose a full year of protection while the larvae keep feeding. This is why I push homeowners to make the treat-or-remove decision in late winter or early spring, not in the panic of August when the canopy is visibly collapsing.
Treat or remove: the decision framework
This is the whole ballgame. Not every ash is worth saving, and not every ash needs to come down. The deciding factor is canopy — how much living crown the tree still has.
When treatment makes sense
If your ash has lost less than about 30–50% of its canopy and has no major structural defects, it’s a strong treatment candidate. The gold-standard method is trunk injection with emamectin benzoate, applied directly into the base of the tree by a licensed applicator. One round protects the tree for roughly two years, so it’s an every-other-year commitment, not an annual one. For smaller ash trees, a soil drench with imidacloprid is a lower-cost option, though it’s less reliable on larger trunks. Treatment is a long-term relationship with the tree — you commit to the cycle, or the beetle eventually wins.
When removal is the call
Once an ash is past roughly 50% canopy loss, treatment rarely brings it back, and I stop recommending it. At that point the tree is declining faster than any product can save it, and every month you wait makes the eventual ash tree removal more dangerous. A tree over your roof, driveway, or a fence gets less benefit of the doubt than one at the back of a field. Sometimes the right answer is removal plus replanting with a non-ash species — and if you’ve also got oaks on the property, it’s worth knowing about oak wilt in Maryland while we’re on site.
Why a dead ash is a removal emergency, not “wait and see”
Ash has a specific, nasty quirk that most tree species don’t: once it dies, it dries out and turns brittle fast — often within one to two years. A dead oak might stand safely for years. A dead ash starts shedding limbs and losing structural integrity almost immediately.
That brittleness is a direct safety problem. Limbs snap with no warning in wind, and the trunk can fail in a storm and land on whatever’s underneath. It’s also a problem for the crew. My climbers can’t trust brittle ash wood to hold their weight, so a tree we could have climbed and dismantled safely a year earlier now has to come down with a crane, or with far more rigging and time. That’s why a dead ash isn’t a project you schedule “eventually.” Sometimes the safer, cheaper move is proactive removal and structural pruning of the trees around it before the ash becomes a hazard.
What EAB treatment and removal actually cost in Maryland
Real numbers, because the price gap is the whole argument for acting early.
Treatment runs roughly $150 to $400 per tree, per cycle, priced mainly by trunk diameter, repeated about every two years. For a valued shade tree near the house, that’s a modest cost to keep it alive and safe.
Removal of a dead ash runs $800 to $3,500 or more, depending on size, access, proximity to structures, and whether the brittle wood forces us to bring in a crane. The same tree removed while it was still structurally sound would land near the bottom of that range; removed as a brittle snag over a roof, it lands near the top.
Do the math over a decade and treatment is often the cheaper path for a healthy, high-value ash — right up until the tree crosses that canopy-loss line, at which point paying to treat a doomed tree is just delaying an inevitable removal.
If EAB has hit more than one tree on your property
Emerald ash borer rarely shows up as a single-tree problem. If you’ve got several ash trees along a property line or a windbreak, it’s common for multiple trees to need attention in the same visit — some treatable, some ready for removal, sometimes with other hazard trees mixed in.
For homeowners facing that kind of larger, multi-tree job, we’re currently running our Clock In Clock Out Discount: get $10,000–$15,000 of tree work for HALF PRICE. It’s built for exactly this situation — a property with enough combined ash removal, treatment, and cleanup work to hit that range. Ask about it when you call for your estimate; we’ll tell you upfront whether your job qualifies.
How we handle ash trees at 855TREEMAN
Our protocol is built to take the guessing out of it. A licensed tree expert comes to your property and assesses the specific tree — canopy percentage, structural condition, location, and how far the infestation has progressed. You get a straight treat-or-remove recommendation, not a sales pitch to do both. If treatment is the call, we time it to the beetle’s window so you’re not wasting a cycle. If removal is the call, we schedule it while the wood is still safe to work.
We’ve served Southern Maryland since 2014, with 790+ Google reviews at a 4.9-star average, and EAB is one of the most common calls we get. The Maryland Department of Agriculture‘s forest pest management program has more background on the statewide situation if you want to read further.
We cover Charles County, Calvert County, and St. Mary’s County in Maryland, plus King George County, Virginia. If you’ve got an ash you’re unsure about, call 855-873-3626 for a free on-site estimate. It’s a fifteen-minute look that can save you a few thousand dollars and a dangerous tree — and if your job is large enough, ask about the Clock In Clock Out Discount on the same call.
FAQ
How do I know if my ash tree has emerald ash borer?
Look from the top down. EAB kills the upper canopy first, so early thinning and dead branches near the crown are the first tell. Then check the bark for D-shaped exit holes about 1/8 inch wide, vertical bark splits, and pale patches where woodpeckers stripped the outer bark chasing larvae. Sprouts pushing straight out of the trunk are another red flag. If you see two or more, call 855TREEMAN for an on-site look.
Can an ash tree be saved from emerald ash borer?
Yes, if you catch it early. An ash holding more than half its canopy is usually a strong candidate for trunk-injection treatment with emamectin benzoate, repeated every two years by a licensed applicator. Past roughly 50% canopy loss, treatment rarely pays off and removal becomes the safer call. The tree’s condition, not its sentimental value, drives the decision. A licensed tree expert at 855TREEMAN can tell you which side of that line your ash sits on.
How much does emerald ash borer treatment cost in Maryland?
Trunk-injection treatment runs roughly $150 to $400 per tree per cycle across Southern Maryland, priced mainly by trunk diameter, and it repeats every two years. Compare that to removing a dead ash, which runs $800 to $3,500 or more once the wood turns brittle and a crane gets involved. For most healthy, high-value ash trees near a house or driveway, treatment is the cheaper long game. 855TREEMAN quotes both options after an on-site assessment.
Is emerald ash borer still a problem in Maryland?
Very much so. Maryland was once under a federal EAB quarantine; that quarantine was lifted in 2021, but deregulation happened because the beetle had already spread statewide, not because the threat ended. Every untreated ash in Charles, Calvert, and St. Mary’s counties is still on the clock. If your ash isn’t being treated, assume EAB will reach it. 855TREEMAN sees new infestations across Southern Maryland every season.
Why does a dead ash tree need to be removed quickly?
Because dead ash turns dangerous fast. Within one to two years of dying, the wood dries out and gets brittle, so limbs snap without warning and the trunk can fail in a storm. That brittleness also makes removal riskier and pricier, since climbers can’t trust the wood and the job often needs a crane. Removing an ash while it’s still sound is cheaper and safer. 855TREEMAN prioritizes dead ash across our Southern Maryland service area.
Should I treat or remove my ash tree?
It comes down to canopy. If your ash still holds more than half its leaves and has no major structural damage, treatment usually wins. If it’s lost more than half the canopy, has heavy woodpecker blonding, or already dropped limbs, removal is the honest call. Location matters too — an ash over your roof gets less benefit of the doubt. A 855TREEMAN licensed tree expert walks the tree with you and gives you a straight recommendation.