I'll go on the record right now: citrus deserves a lot more talk and a lot more research than one article can give it. This is a deep topic, it's controversial, and there's a lot of money tied up in it. But people ask me about citrus all the time, so here's my honest take.
How we got here
It goes back almost a hundred years. For decades, the industry squeezed and squeezed to get better flavor, fewer seeds, bigger yields. Every round of that narrowed the genetic diversity, that means how different the trees are from each other underneath. Farmers got pushed hard to grow more for less, and big ag and the chemical companies were happy to sell them the way to do it.
So here's what a lot of Florida citrus looked like. Thousands of acres of one single variety of orange. Planted on sand, in full sun. Weeds sprayed with herbicides, bugs sprayed with pesticides, and irrigation running constantly because the soil couldn't hold any water. Barely any mulch. The runoff was terrible.
And when every tree in a field is genetically the same, every tree has the same immune system. If a disease shows up that one tree can't fight, none of them can.
Then greening showed up
In the late 1990s, a tiny insect from Asia showed up in Florida, the Asian citrus psyllid (Diaphorina citri). It carries a bacteria that causes citrus greening, also called HLB. Once a tree has it, there's no cure.
It has devastated Florida citrus. The state's orange crop is down roughly 90 percent from its peak. It's hurt farmers all over Florida, and a lot of that old grove land is getting bought up and turned into something else.
Here's what bugs me. For years, almost all the research was done inside that same farming system. Nobody was studying citrus grown with healthy soil life, insect diversity, native plants, and organic pest control. We don't even know if there's a native insect out there that would eat the psyllid, because in those groves everything got sprayed. There were no good bugs left to find out.
The oak tree connection
This is the part that gets me excited. Researchers at the University of Florida noticed that citrus trees growing near laurel oaks (Quercus laurifolia) looked healthier, and had less of the greening bacteria in them. Oak leaves are full of natural compounds like tannins, and the thinking is that rain washes them off the leaves and into the soil and the citrus. When they soaked oak leaves in water and poured it around sick trees, those trees grew bigger roots, greener leaves, and less bacteria.
Some growers will tell you they have trees that test positive for greening and show no signs of it at all. Green leaves, happy tree, great fruit.
Now, honest caveat: nobody is calling this a cure, including the researchers. It's a tool. But it's a really promising one.
How I'd grow citrus here
Plant it under or near an oak. A laurel oak or a live oak throws shade during the brutal afternoon sun, so the tree holds more moisture and doesn't get as stressed out by our heat. Citrus actually appreciates a little less sun than people think.
Collect your oak leaves and use them. Let them build up under the tree as mulch and organic matter.
Build the soil. A grove tree on a sand hill is just sitting there waiting for the irrigation to turn on. No water held in the ground, and no soil life, because it's getting baked by the sun or killed off by chemicals. What you want is the opposite: rich soil full of microbes, mulch, and native plants around it bringing in the good bugs. Read more about that in my article on natural pest control.
Feed it right. A tree that's well fed with organic nutrition has a better immune system to fight back. That's what my fruit tree care program is built around.
My honest bottom line
I grow citrus this way. I believe in it, and I encourage you to try it too. But I don't guarantee citrus trees, and this is exactly why. There's no 100 percent cure yet. Citrus is not a beginner plant, and don't be surprised if your tree gets greening and dies. There are growers who dedicate their whole lives to this, and it's still really challenging.
If you want something that will reliably feed you, start with my top fruit trees list. If you've got your heart set on citrus, let's talk about the right spot for it. It starts with a consultation.