What’s Wrong With My Plant? A Diagnostic Guide

Every sick plant is telling you something — here’s how to listen

Plants can’t talk, but they’re excellent complainers. Yellow leaves, spots, wilting, things with too many legs — every symptom is a clue, and most garden mysteries are solved by matching the clues instead of guessing. This tool does the matching: tell it what kind of plant is struggling and check off what you see, and it ranks the most likely culprits.

A few diagnostic habits that make everything easier: look at the whole plant first (is it one branch or the whole thing?), flip the leaves over (half of all pests live on the undersides), note which leaves are affected (old vs. new growth tells nutrients apart), and think about what changed (new mulch? cold snap? neighbor spraying?). The “how to confirm” notes on each result walk you through the check.

How to use this tool

• Step 1 — pick the plant type (or skip it to see everything).
• Step 2 — check every symptom you see. More checks = better ranking.
• Read the results top-down — each card shows how many of your symptoms match, how to confirm the diagnosis, what to do about it, and a regional note.

Cards tagged ⚠ Act fast are the ones that spread or kill quickly — citrus greening, southern blight, chinch bugs. Don’t sit on those.

The honest limitations

This is triage, not a lab test. Similar symptoms can have very different causes (iron deficiency and root damage both yellow new growth), and some problems need a microscope or a lab to confirm — root-knot nematodes and many diseases included. For valuable plants, food crops you’re counting on, or anything spreading fast, your local cooperative extension office will diagnose it properly, usually for free or close to it. There’s no shame in a second opinion — even professionals send samples to the lab.

A note on “doing something”

The urge to spray first and diagnose later is strong, and it’s how plants get hurt twice. Most problems on this list are fixed with cultural changes — water, mulch, airflow, the right plant in the right place — not chemicals. When treatment is warranted, the cards lead with the least-toxic options that actually work. And a few entries have no cure at all (we’re looking at you, citrus greening); the honest move there is management and prevention, not wishful thinking.

Keep Growing 🌱

Where to go next:

• Living Soil for Florida Gardens
• I Have a Vegetable Garden. Now What?
• Compost vs worm castings