Yellow azalea leaves with green veins?

1. Look at the pattern, not just the color.

Are the spaces between veins yellow while the veins stay green, especially on newer leaves? That pattern can fit iron chlorosis: the plant cannot obtain enough usable iron. It does not prove that the soil contains too little iron.

Note whether the affected leaves are new or old. If only older inner leaves are changing, use the azalea rescue guide to check seasonal leaf changes first.

2. Check moisture and recent care.

Look for persistent wetness, poor drainage, deep planting, or recent heavy feeding. Damaged or poorly aerated roots can limit nutrient uptake even when nutrients are present. Adding iron does not repair those conditions.

Check container drainage without digging through the shallow roots. If leaves are also wilting or developing dry brown areas, follow the brown-leaf and wilt checks.

Confirm the plant type, too. A florist azalea, often Rhododendron simsii, is frost tender; yellow leaves are not a reason to plant it outdoors in a freezing climate.

3. Test before changing the soil.

1. Ask a local soil-testing service for sampling instructions. Say that you are growing an azalea; for a container, ask whether it accepts potting media.
2. Use the result. High pH can make iron unavailable. If pH is already suitable, adding more acid may create another problem.
3. Choose a measured response. Discuss confirmed chlorosis with local Extension. Iron products may help symptoms, but drainage or unsuitable soil still needs attention.

Maryland Extension advises against aluminum sulfate for azaleas. Repeated acidifying fertilizer can also push pH too low. There is no universal dose for an unknown soil or pot.

4. Compare the next growth.

Photograph the same shoot and keep the test result with your care notes. Worsening yellowing despite suitable pH, especially with wilt or branch death, deserves diagnosis before another supplement.