Sometimes, it seems as though plant problems in our yards and gardens pop up out of nowhere. One minute you think you’ve got a landscape in pristine health and the next, you’re like, “why is my tree looking so bad!?”
Most plant problems don’t happen that quickly. I’m going to give you some of my tips and tricks for identifying and tracking plant problems in your yard and garden.
1. Know what is normal for the plants in your landscape.
This step might seem silly, but in fact, there is so much variability across plants and cultivars. And knowing what is normal is the first step to being able to quickly and accurately identify when there is something not normal going on with your plant(s).
2. Characterize the symptoms
Anything that is not normal with a plant or disrupts the normal function of the plant or its parts is a symptom. Symptoms come in many shapes and sizes and can affect literally any part of a plant, depending on what is causing the symptoms. While it’s up to us in the Plant & Insect Diagnostic Clinic (PIDC) to determine what is causing the symptoms, the ability of our clients to characterize the symptoms themselves is really helpful. Here’s a short list of some words we use to characterize symptoms:
- spots
- blotches
- necrosis (dead tissue)
- chlorosis
- rot
- wilt
- blight
- stunting
- dieback
- galls
- mosaic
- distortion
- and many, many more!
When characterizing symptoms, use as many descriptive words as possible, too, noting things like colors. (e.g., the leaf has small spots that are brown in the middle and yellow around the outside, and the spots can be seen on the top and bottom of the leaf.)
3. Note the date of symptom onset
Depending on the cause of the plant problem, some problems progress in severity over time. By noting the date that symptoms are first observed, you can track whether the problem on your plant(s) is stagnant or getting worse, and you can also note whether the problem stays in one spot or moves to other plants in the environment.
4. Observe and note any patterns
Plant problems often have patterns to them. Looking for and identifying patterns to plant problems is invaluable to plant problem diagnosticians. There are actually several different types of patterns to look for.
- Within a plant: Are the symptoms affecting plant parts more at the bottom or top? Randomly distributed throughout the plant? Is only one section of the plant affected? Etc.
- Within a plant part: On the plant part(s) affected, is there any pattern? For example- symptoms are occurring between the leaf veins (interveinal), symptoms along the leaf edges (margins), symptoms seen on top of the leaf and not bottom, etc.
- Among plants of the same species: If multiple plants of the same species are present, are all the plants affected? Just one? Just a few? Etc.
- Across species: Do similar symptoms show up across plants of different species or not?
- Across a space or field: Is there any pattern to plants affected across a given space or garden? i.e., are plants closer to the road affected than those closer to the house?, the east side is worse than the west side, etc.
5. Keep records and take photos!
Take photos the first time you see symptoms on your plant(s). Keep notes and continue taking photos as time passes. This will also help you determine whether things are progressing in time and space.
Also, record keeping includes knowing background information about your plants and management/care methods applied to them. Things such as the age of the plant, watering practices, chemicals applied (herbicides, fungicides, insecticides) in the environment, soil amendments, mulching, etc., are examples of critical background information for determining plant problems.
6. Remember, accurate diagnosis is key to management
To be a good steward of your property and the environment, using integrated pest management (IPM) is highly recommended. One of the tenants of IPM is to apply management methods only after you’ve got a confident diagnosis. We don’t expect our clients to be able to diagnose plant problems themselves; that is why the PIDC is here. Send us a sample once you’ve identified a plant problem. If you’ve followed tips & tricks 1-5, sharing that information will also help us in our diagnostic efforts.
Final thoughts:
In the PIDC, our diagnostic efforts only go so far as to determine whether there is a pathogenic cause of a problem. If there are environmental stresses affecting a plant, our management recommendations can only go as far as the amount of background information our clients provide us. In years like this, where most plant problems have no pathogenic cause, we are left grasping at straws to determine what environmentally could be causing the plant problems we are seeing. The more we know about patterns, date of symptom onset, and any care history for the plants we are seeing, the easier it will be for us to conclude what is causing the plant problem. And only when we determine what is causing a problem can we provide you with the vital information you need to save your plants.
Links to this article are strongly encouraged, and this article may be republished without further permission if published as written and if credit is given to the author, Yard and Garden, and Iowa State University Extension and Outreach. If this article is to be used in any other manner, permission from the author is required. This article was originally published on July 11, 2023. The information contained within may not be the most current and accurate depending on when it is accessed.