Plumeria – black tips. Disease or not?

Question

Dear Sir or Madam, I would like to ask you for your opinion on health conditions of my plants. I got two plants that were bought as cuttings (this July) so I had to root them in the bag. They seem to develop roots quite nicely so I transferred them into the pot. New leaves started to grow and everything looked good. After two months in the glasshouse, leaves got brown spots and are coming off (probably preparing for winter and going dormant). Anyway, tips are turning black and since I am plumeria newbie, I am not sure if this is common feature with upcoming winter or if it is black tip disease. Other possibility is tha could be sunburn since plants were grown in direct sunlight while rooting. Two days ago, I bought new plant -already rooted – and I notice the leaves are brown as well. Hopefully, they are just going dormant… Can you tell me your opinion on those picture? I live in the Czech Republic (central Europe) so climate is quite mild.
Many thanks, Bartolomej.

Answer 1

Plumerias do typically lose their leaves for the winter, except in very warm tropical areas. They seem to be triggered to lose leaves when the days get shorter, the light level drops, or the temperature drops.

The black tips don’t look too bad. Make sure no part of the stem is mushy. As long as the stem is firm, it is probably fine. But if the black part gets worse or spreads down the stem, applying some fungicide would probably be best.