The normal cycle for Plumeria's is they do what you described what your plant is doing in the fall before going dormant for the winter. When your plant is in that stage, it's wise to cut down watering drastically and even ok to stop all together when it's dormant. Then come spring time repot, water one good time and don't water again until you see leaves.

Squeeze the stalk at ground level. If it's mushy, then you have root rot and your plant is dying. It can be saved but it will require you to cut out the bad and start over. If it's still solid then do not water again until the soil has dried out. Add a tbls of Epsom salt to a gallon of water then water your plant.

Hard to say without pictures. Were the bottom most leaves yellowing and falling off first? How does the branch tip(s) look? Are they producing?

The stem is completely firm, no sign of tort but the leaves falling off are not just from the bottom. I'm not overwatering, I use a moisture meter to test how dry the soil is before watering again. It's in cactus soil.

Hi Ashley I had one do the same thing this year dropped all leaves I think first_kms correct about it having a small case of black tip may have got a little cold if it were mine I would just watch it for a while and see if it puts on new leaves

roger

Hello everyone, thank you for your replies! Figures I get the fussy species of plumeria. I tend to attract drama into my life :p

I have not noticed any insects but i bought a insecticide and gave it a sprits and I will monitor it. When I repotted the plant the roots were nice a healthy, no sign of rot so not sure whats up. It's probably a combination of a few things. I have now placed it outside where it's nice and warm and will getting morning and afternoon sun. It was in a sunny window (afternoon sun) during winter so i'm not too worried that its too much light.

As I mentioned plumerias were new to me and I had no idea what to do with them. So come fall i'll put them in my basement where its cool, minimal light, and allow it to go into dormancy and will not water. I just have my fingers crossed I may get even a few flowers this year.

HI Ashley I would put back where you had it last year the Singapore obtuse don't like to go dormant main thing is keep it warm you may try putting it on a heating pad when it gets cold. cool & damp is what causes it to get black tip

Ok, so no to dormancy. Should I stop watering it too when fall comes? Or just very little water?

Just very little water

This is one sad looking plant, lol! It has continued to drop leaves and there is no infestiation of bugs so I don't know what's it's deal.

Also, if the tip where the new growth comes from suppose to look dark brown?

The tip looks good to me. Its just being poky.

So it’s blooming. All I did was put it in the sun and I literally forgot about it. Didn’t water it, nothing.... looks like it worked.

LOL, Typical passive aggressive Singapore behavior. Great to see it producing blooms. thanks for the update