Pest & Disease Control · CDA Licensed Applicator
A great many of the trees we are called out to “treat” do not have the problem the homeowner thinks they have. Iron chlorosis gets treated as drought, borer damage gets treated as disease, and the tree keeps declining while money goes into the wrong bottle.
Diagnosed first, treated second — and only when treatment is actually the right answer.
Free on-site assessment · Written quote · No obligation
These four account for most of what we find, and three of them get misdiagnosed constantly.
Confirmed in Aurora in September 2025, in Denver in July 2025, and in Littleton back in June 2023. Ash is roughly 15% of Colorado’s urban forest — in Aurora alone there are about 110,000 ash trees, and around 90% of them stand on private property, which makes them the owner’s decision.
Yellow leaves with green veins, worst on the newest growth. Our soil is alkaline, which locks up iron the tree cannot then absorb. It is extremely common, extremely treatable, and constantly mistaken for drought stress or disease.
Small popcorn-like pitch tubes on the trunk, fading needles from the top down. Stressed and drought-weakened conifers are the ones that get hit, which is why watering is part of the answer and not a separate conversation.
Sunken, oozing patches on spruce and aspen limbs, or blotched and curling leaves in a wet spring. Both are fungal, both are managed rather than cured, and both respond very differently depending on how far along they are.
Anyone can spray a tree. The value is in knowing whether it needs spraying at all.
Canopy, trunk, bark, root flare and the soil it is standing in. Most of what looks like a leaf problem started underground — compaction, poor drainage, or a tree planted too deep a decade ago.
Which pest or condition, how far along it is, and whether it is worth treating. If the honest answer is that the tree is too far gone, you will hear that instead of a treatment plan.
Trunk injection, soil application or targeted foliar spray, applied under a Colorado Department of Agriculture licence. Some of these have narrow windows in the year and doing it in the wrong month wastes your money.
Iron chlorosis treatment usually shows in the canopy within about four to six weeks. Borer protection is preventative and you see nothing at all — which is exactly the point.
Nearly every complaint people have about tree companies comes down to the same thing: something happened that the homeowner never agreed to. These five exist so that cannot happen here.
Treatment is nearly always cheaper than removal and replacement. But there is a point on every declining tree past which you are paying to delay the inevitable, and we will tell you when you have reached it.
Trunk diameter, because dosing is by size. The number of trees. Repeat applications where the programme calls for it. Difficult access for equipment. Conditions that need several years of management rather than one visit.
Catching it early — by a wide margin the biggest factor. Treating several trees on one visit. Combining a treatment with pruning already scheduled. Preventative protection, which costs far less than rescuing a tree already in decline.
The diagnosis. The arborist’s opinion on whether to treat at all. The written quote. And being told to save your money, which happens more often than you would expect.
A tree that is yellow from alkaline soil will not improve from an insecticide. A tree full of borers will not improve from fertiliser. Both mistakes cost a season, and with some pests a season is the difference between a treatable tree and a removal.
★★★★★
“Derek… refused to try to upsell me on treatments I didn’t need but had been quoted as necessary by two other companies. He also was not afraid to let me know I could check with an independent source as to whether his assessment was correct compared to the others.”
— Michael H. · Verified Google Review
★★★★★
“He could definitely have sold me on unnecessary work, since I don’t know much about trees. Instead, he reassured me not to worry about several things… My invoice was for the quoted amount and no more.”
— Wendy B. · Verified Google Review
★★★★★
“Very professional and took great care to protect bushes around the trees being trimmed. Owner is a certified Arborist, that made a huge difference compared to the previous tree companies I used.”
— Google reviewer · Verified Google Review
Usually not — yellow leaves with green veins almost always mean iron chlorosis, which is a soil problem, not a disease. Colorado’s alkaline soil locks up iron so the tree cannot absorb it. It is one of the most treatable conditions there is, and it is also one of the most frequently misdiagnosed. An arborist can tell the difference in about a minute on site.
It depends where you are, and the list keeps growing — which is why we never guess. It was confirmed in Boulder in 2013, Littleton in June 2023, Denver in July 2025, Aurora in September 2025, and Parker in August 2026. Before we quote anything for an ash, we check the current confirmed status for your address rather than working from a number we remember.
An ash caught before the canopy has thinned badly usually can be. One already well into decline usually cannot. The practical threshold most Colorado specialists work to is roughly a third of the canopy lost. Past that, the tree is spending what it has left and treatment becomes money spent delaying a removal. An arborist has to look at the tree to tell you which side of that line yours is on.
No. We use the narrowest method that will actually work, and that is often trunk injection rather than spraying at all. Injection puts the product inside the tree, which keeps it away from your beds, your pets and your neighbour’s property. Where a spray genuinely is the right tool we say so, explain it, and apply it under a Colorado Department of Agriculture licence.
One certified arborist behind all of them, and one written quote if you need more than one.
Tree Removal · Tree Trimming & Pruning · Stump Grinding · Tree Injections · Lawn Fertilization & Weed Control
The diagnosis is free, and on a declining tree it is the single most valuable twenty minutes available to you. Treating the right problem early is almost always cheaper than removing the tree later.
312 Norfolk St, Unit A, Aurora, CO 80011 · Monday to Friday, 8:00 AM to 5:00 PM · Serving the Denver metro since 2003