I don't know anything about Plumerias but I like your plant. :-D

One thing I can offer, with respect to aphids: 1) always follow the label directions on pesticides and mix according to that. As long as the plant is listed as one that is safe to use the product on, it should be OK. Do not assume that using more than recommended will somehow be better. 2) Insecticidal Soap is very effective against aphids and harmless to plants, people and pets.

Thanks @Toxcrusadr :)

I did follow the usage instructions the first time I used it, but the second time I ended up adding a few drops extra by mistake. It was a stupid, hasty mistake! I'll keep a check on my plant in the coming few days to see if there has been any negative effect of the medicine on it.

Insecticidal Soap? Okay, I'll look that up on the internet! Thanks a lot :)

So sorry my comment wasn't getting posted so I did it a couple of times and now it has been published so many times! And now there's no way to delete them!

Hi, if you're worried about pesticides hosing off aphids with a strong stream of water usually helps. I also brew a strong garlic tea and the aphids hate it. Your plant doesn't seem unhealthy. I'm not sure what zone you are in but it will take off with plenty of sunshine & food. Since it's a sentimental plant you may want to start a cutting it 2 to preserve it justin case.

As for the soil as long as it drains well you should be ok. A good time release good is osmocote.

Hi @Carlotaroser,

thanks a lot for your suggestions. We are in Bombay (India) which has a usually warm and humid summer, a proper monsoon, and a relatively cooler winter with the sun still shining. So even in its dormant period, my plant receives sunlight. I guess that's why it doesn't shed off all its leaves.

I'll definitely consider preserving the plant by rooting the cutting.

The soil I am unsure of. When I put my finger in the soil, it sticks to my finger because that's how moist it is inside. I am wondering how to deal with that.

Osmocote? Is that a fertilizer?

Also, is it advisable to use a liquid fertilizer for Plumeria? I have read that spraying liquid fertilizer on the foliage helps it receive nutrition more effectively.

Any recommendations on this?

Imidacloprid is ok to use on Plumeria. My preference is to use Neem oil for insect and mite control as it is not as harmful to pollinators. The amount of moisture a Plumeria tolerates in the soil depends on how much sun it gets, time of year, and soil conditions. Just based on the images posted I don't think over watering is an issue. The leaves on the ground may be from the insect issues and treatments but if it were to continue yellowing and dropping leaves then it might actually be too dry.

Hi @the_first_kms2,
thanks for your insights! That's quite helpful. The leaves on the ground are from other trees in the park. But if your guess is that the soil might be too dry, how do I check that? I can't afford a kit so is there a DIY way to check for how moist the soil is?

Most of us use the finger test just like you.

You have right climate..they love hot. What they also thrive on is consistent watering...not constant dry to wet. Since this is not your yard but a park..look for where the irrigation reaches it to ensure its survival.