Earlier this year I attended a talk on plant disease diagnostics as part of my continuing education as an ISA Certified Arborist. The talk was given by a highly respected individual whom I have had the pleasure of learning from since my early days as an arborist in central Ohio. This time, one of the first statements spoken caught my attention immediately. I paraphrase it into something like this:
When it comes to health, humans have spent most of their time and effort studying diseases of one single organism – humans. And when we go to a doctor and he or she does not have an immediate answer for what might ail us, we don’t shake our head in wonder and ask “Why? Why don’t you know what is wrong with me?” The doctor may prescribe certain tests to start to gather information on what is wrong with us, and we consider that to be a normal process.
In contrast, arborists and horticulturalists are faced with hundreds of species of plants, each with their own specific array of pests and diseases, and when faced with a problem we can’t immediately identify, saying “I don’t know” may not be considered an acceptable answer by the person whose plant we have been called to save.
This is a difficult subject for me to write about, but maybe sharing a bit of what goes through my mind when trying to figure out what went wrong with a sick or dead plant will help you as a plant owner see how things sometimes go, from an arborist’s perspective.
When I walk up to a plant that is declining, dying, or dead several things go through my mind. They are all based on the scientific concept of the disease triangle (Kenny put together a great summary here), but here are the steps I am following in my mind:
What is the species of plant? Does it look normal for its type?
What are the common issues this plant typically faces? Do the symptoms I am seeing match any of these issues?
What is the immediate environment of the plant? Is it what this type of plant needs to thrive?
Are there signs of pest predation? If no, is the problem root related? If yes, why are the pests here?
My thoughts will go back and forth among these general areas because so much is interconnected. For example, I may see borer activity near the base of the plant, but is that really the causal issue? Perhaps the plant is waterlogged, and has begun to produce alcohol because of that. The alcohol has attracted boring beetles. In this case treating the plant for borers will not make a difference to plant health – they are secondary to the fact that the plant is stressed by environmental conditions.
My main goal as an arborist is to give tree managers (current landscape owners) the best information I can so they can make the best decisions for their situation. For example, some pests and diseases can be treated with high success rates, others not so much. Some treatments, such as fungicide applications, are mostly preventive, and need to be applied frequently through each season for the best chance at being effective. All of this is communicated to the tree manager so the best decision can be made.
There is one thing I can assure each of you of, with confidence: If I know what is wrong with your tree, I will try to walk you through whether treatment is a good option or not. I may say, “X is a known prescribed treatment for this problem. Experience has shown me that sometimes trees respond well to this, and sometimes they do not. Here is the cost of X – it may or may not be the best approach for you or your tree”. You weigh your options and decide what makes the best sense to you. The tree may be an essential part of your landscape, or have great emotional value, meriting a “let’s do everything we can to save it” approach. On the other hand, it may be a tree you really don’t mind phasing out of your landscape, to make room for a tree that is better suited to that particular environment.
Things can get tricky though…
What about fertilization? Well, in most urban landscapes soil quality has proven to be very substandard compared to what trees and shrubs need to thrive. So we commonly recommend a general fertilization to help maintain good health for trees and shrubs. The product we use in particular is very good for this purpose: a low nitrogen formulation blended with organic products that help condition the soil as well as provide nutrients. (Why this is a good formula for trees is a topic that really needs to be discussed, but far larger than space in this installment will allow). Before I get to my word of caution, let me ask two questions:
We know that having good nutrition as people is essential for good health. But will eating the right foods guarantee good health for the rest of your life?
We take our pets to the veterinarian for their regular shots and checkups. Does this guarantee that our pets will never fall ill?
Both scenarios are true for trees, but sometimes I face tough questions from clients whose trees I have been caring for. “You fertilized my trees and shrubs, and now my shrubs are dead.” “I was told by another arborist that my oak had an iron deficiency, and you said to give it manganese instead. It has still not improved.”
I understand where questions like these come from, and I do not want to take them lightly. But I suppose my goal is for people to understand something crucial: I will prescribe what I believe to be the best approach for the health of a given plant, but trees and shrubs can still die. Sometimes I don’t know why. When that happens, there are only a few reasons that hold true:
I prescribed an incorrect treatment. If I did so knowingly, I am a charlatan, and not to be trusted. If unknowingly, perhaps I need more training, or it was a simple mistake.
I prescribed the right treatment, but conditions were such that the tree was too far in decline to begin with.
Something else besides what was being treated for caused the tree to die.
For the first reason, reputation serves to keep me in the clear. Reputation is based on how many people have experienced my service over time. As for learning, hopefully that never stops.
For the second reason, this happens more than I would like, but is only reasonable since by the time a tree is noticeably sick it has usually suffered for several years already. When I recognize this in a tree I try to steer people away from treatments that may not be successful even though they are the proper treatments to prescribe.
The third reason happens quite often as well, especially when environmental conditions change from one season to another.
So where does that leave us? The meaning of a treatment being prescribed and applied by an arborist of good reputation is that he or she believes it is the best next step needed to address a problem. Conversation and questions are always welcome, but we all know that sometimes the answers are not easy. Sometimes the answer requires humility and truth, and it may simply be “I don’t know. Let’s figure out what the next step is.” I have been with Russell Tree Experts for 8 years now, and there have been some difficult moments. But I am happy to say those are in the minority by far! There are many trees I can think of that have responded well to treatment, and are still alive because of it. And there are many tree owners who have lost their trees after attempting treatment who are still able to trust that we did what we could and for whatever reason it just did not work. Both of these scenarios are triumphs in my mind, because both scenarios represent the same good faith effort undertaken by arborist and tree manager working together.
Thank you for taking the time to read this lengthy article. I hope to visit with you in your landscape soon! I would also like to thank Shari Russell, TJ Nagel, and Annette Durbin for taking the time to read and comment on the first draft of this article.
Your friendly neighborhood arborist,
José Fernández | Regional Manager, Russell Tree Experts
José became an ISA Certified Arborist® in 2004, and a Board-Certified Master Arborist® in 2015. Currently he is enrolled at The Ohio State University pursuing a Master’s Degree in Plant Health Management. José likes working around trees because he is still filled with wonder every time he walks in the woods. José has worked at Russell Tree Experts since 2012.