I have three potted plumeria. Two (one older and one from a cutting last year) are doing fine (see below). One of the older ones just started getting sick (third image below).

All three get bi-weekly fertilization when watered with 12-55-6.

They are potted in cactus mix since last summer.

Daytime temps are in the upper 80s to 90s. Nightime temps are in the upper 50s to 60s with overcast mornings occasionally.

The problem one just started dropping all its leaves last week. It is going to bloom but all the leaves are dropping off so I am sure it is stressed now and so am I!

Please help!

Might be rust fungus, it will affect the foliage but not the stem or flowers. Get it away from your other plants as it can easily spread. You can try fungicides to try to clean it up. Discard all fallen leaves as they can contaminate other plants and keep it in a well ventilated area. If left untreated it could loose all of its leaves. If it is rust you can save the plant.

You're also going to want to take those saucers out from under your pots. You want the water to drain out. No wet feet.

Hello thanks for the help!

I realized I have you at a disadvantage as I can see the leaves close up and all you have is pictures.

I am attaching more images of just the leaves close up.

I hope you can see there is no yellow powdery stuff on the leaves like I see with rust images.

Rather this problem starts as at a very specific area on the leaf near the central vein and then other sections along the leaf do the same thing.

Also I failed to mention in earlier post that the plants get morning sun about six hours and then afternoon shade but the leaves are never watered or wet.

Is it possible the 12-55-6 liquid fertilizer I am using to water them is burning the plant?

However why is just this one plant affected if all three get the same feeding?

The reason I ask about fertilizer burn is it did happen to me last year but with all three plants not just this one?

Thanks again for all your information and invaluable insight!

Hi there, Your closeup pictures of the leaves AND THE POOL in the background lead me to believe perhaps the leaves had some of your pool chemicals affect the plumeria. Either by say the chlorine dust or winds from the vapors from a pool shock or just everyday evaporation of the chlorine or other chemicals from the pool mixed with heat or humidity. Be careful if you use a lawn service for your grasses too. My essential oils to keep away insects (peppermint and citronella) had a similar reaction when drops were placed in the water fountain. Easily solved by moving the pot upwind instead of downwind. The plumeria survived.

Spider mite damage is usually on the central vein area of the leaf. Your pool is not the problem. I have plumeria around my pool with no issues. As long as you're not directly and consistently throwing pool water on your plants they should be fine.

I used to water my plumeria with pool water. I never noticed any problems doing so.

That looks a whole lot like sun scorch, regardless of whether the others are suffering too. See what you think:
https://garden.org/thread/view...

Hello Everyone:

Thank you all for your help.

I started flooding the pot several times with distilled water and it appears the damage has stopped for now.

The plant lost most of its leaves but the new ones appear healthy (see picture) and have no more leaf damage yet.

So my thinking is it was too much fertilizer started the problem but WOW the leaf damage sure went fast!

The damaged one is front one in the picture.

Now I have a new problem.

The big one behind in picture is doing really well and about to bloom but is SOO top heavy!!

Any thoughts how to support it till after the summer so it can bloom and not break?

After summer I can cut it but for now since it is first time blooming don't want to mess with it so any thoughts on how to support it would be helpful!!

I just had one that was doing the same thing. The pot was too light, and the leaves acted like sails. I just finished up-potting it into a much heavier pot. I also added a few big rocks near the bottom of the pot. That plumeria won't fall over anymore.

I agree, I would up pot all three to be done with it for a couple years. It was mentioned earlier to lose the saucers to allow more drainage.
I personally use plastic pots and remove the bottoms for maximum drainage. 55% phosphorus is a little high on the scale but its usually nitrogen that burns leaves, although 12% is not to high. They look great, I'm glad you recovered them😎