If you've searched for help with a sick palm or a struggling oak in Tampa Bay, you've probably run into the word Arborjet. It's the name of a tree injection system, and it has become shorthand for a whole approach to tree care: instead of spraying a tree from the outside or drenching the soil, you deliver the treatment directly into the tree.
It's a genuinely useful tool. It's also not a cure-all, and a good tree care company will tell you when it won't help. Here's what trunk injection actually does, what it's used for in Florida, when it beats spraying, and the cases where it's the wrong answer.
How tree injection works
A tree already has a plumbing system. Water and nutrients move from the roots up through the trunk to every leaf in the canopy, and trunk injection uses that system.
Small ports are placed at the base of the trunk, into the living tissue just under the bark. A measured dose of treatment, whether nutrients, an insecticide, a fungicide or an antibiotic, goes in under controlled pressure. The tree then carries it upward and outward on its own, typically within days. The ports are small, and a healthy tree closes the wounds as it grows.
The simplest way to think about it is an IV instead of a pill: the medicine goes straight into the system that distributes it.
What it treats in Florida
Palms. Florida palms are where injection really earns its keep.
- Nutrient deficiencies. Palms in our sandy soils often run short of key nutrients, which shows up as yellowing, frizzled or stunted new fronds. Injected nutrients can green a palm up faster than soil feeding alone, while a proper palm fertilizer program fixes the underlying shortage.
- Lethal bronzing prevention. Lethal bronzing is a fatal palm disease that has killed palms across Tampa Bay, including sabal palms, Florida's state tree. University of Florida guidance recommends preventive antibiotic injections for healthy palms near infected ones, repeated every three to four months. (UF/IFAS: Lethal Bronzing Disease)
Oaks, magnolias and other specimen trees.
- Insect pests. Scale, aphids and wood-boring insects can all be treated from the inside. Borers in particular are hard to reach with a sprayer, because they live inside the wood.
- Fungal and bacterial disease. Some diseases respond to injected fungicides or antibiotics, especially when they're caught early.
When injection beats spraying
- Big trees. A mature live oak or a 30-foot palm is very hard to cover completely with a sprayer. Injection reaches the whole canopy from the base of the trunk.
- Near people, pets, pools and water. There's no spray drift onto the patio, the pool, the neighbor's car or a nearby pond.
- Rainy season. A spray applied before a Florida afternoon storm can wash off within the hour. An injection is already inside the tree.
- Precise dosing. Each tree gets a dose based on its species, size and condition, instead of whatever happens to land on it.
- Pests that hide. Insects living inside the wood or under scale covers are protected from sprays. They aren't protected from what the tree itself carries.
When it won't help
This is the part that matters most, because a treatment that can't work costs money and time a tree may not have.
- Ganoderma butt rot. This fungal disease rots the base of a palm's trunk. There's no cure, injected or otherwise, and an infected palm needs to come out before it falls.
- Palms already showing lethal bronzing. Injection is preventive. Once a palm shows symptoms, the antibiotic can't reverse the disease, and the palm should be removed to protect the ones nearby.
- Problems that start in the ground. A tree planted too deep, roots damaged by construction, soggy or compacted soil, or trunks nicked by string trimmers won't be fixed by anything injected into them. The cause has to be fixed.
- Healthy trees, just in case. Every injection is a small wound. Done for a real reason, it's a very good trade. Done routinely on a tree that doesn't need it, it isn't.
That's why diagnosis comes first. The right question is never "should I inject my tree?" It's "what is actually wrong with it?"
How long does it last?
It depends on what's injected and why. Preventive antibiotic programs for palms are repeated every three to four months. Some insect and disease treatments protect a tree for one to three years. Your arborist should give you a schedule and tell you what to watch for between visits.
Start with a diagnosis
We have an ISA Certified Arborist on staff, and every injection recommendation we make starts with looking at the tree itself: its species, its age, the symptoms, the soil, and the trees around it. Sometimes the answer is injection. Sometimes it's a better fertilizer program, a drainage fix, or the hard news that a palm needs to come down.
Learn more about our Arborjet trunk injection service, meet our certified arborist, or call us at (813) 920-8041 to schedule an assessment.
Frequently asked questions
Does tree injection hurt the tree?
Each injection makes a small wound, which a healthy tree closes as it grows. That's why injection should be used for a diagnosed problem, not as routine maintenance on a healthy tree.
Can trunk injection save a dying palm?
Sometimes, if the problem is a nutrient deficiency or a treatable pest caught early. It can't save a palm with Ganoderma butt rot, and it can't reverse lethal bronzing once symptoms appear.
How often do palms need to be injected?
For lethal bronzing prevention, every three to four months, according to University of Florida guidance. Nutrient and pest treatments follow their own schedules, which your arborist will set.
Is injection better than spraying?
For large trees, trees near pools, people and water, wood-boring insects, and Florida's rainy season, usually yes. For small shrubs and some surface pests, a targeted spray can still be the simpler answer.