There are so many smart people here, that maybe many can help you seperate true tropical plants from those that are not. I think you might even have some sud-tropical ones. I know that certain citrus, jasmine and olive that I have can handle temps that low, but much prefer the 50's. In fact, olive and some jasmine are required to have these temps to set bloom. Plumeria if you keep them on the very dry side, rest. Clivias can set bud. .. I would probably do a search on each plant and find out what tolerates and requires certain temps... If it were me and my room was getting below the 50's, I would put an electric heater on a timer, a thermomter, and a humidifyer with constant air movement by fan and keep the temps warmer. Maybe some here can help identify the ones that actually need cooler temps to thrive. I am horrible with names.. Sorry. Too, you could empty all those plants out of the room before you loose them if you do not use heat and are not sure. Tropicals are just that, and love warmth, thrive in warmth. If you don't provide these temps, then most just might hang on or die from root temps being too cold. Also watch out for watering. It only takes once when the soil stays damp too long before rot sets in on most these plants. Try to water sparingly until the temps rise. Goodluck.. If it were me, I would invest in a small heater and keep it warmer..That is what I do.. Mike..;-)

It isn't at all unusual for plants within the same genus to have very different cold tolerances. To give an example from the banana world, most species of Musa are very tropical and frost tender. But there are some species of the genus Musa that show impressive degrees of cold hardiness. Musa basjoo (Japanese banana), for example, is commonly overwintered in cold winter zones (down to zone 6 with mulching). It's not a coincidence that this hardiness is associated with a species native to Japan (where a degree of cold is characteristic of the winter season). The genus Amorphophallus is represented by many species, most tropical, many subtropical, and a smaller number of species able to survive to colder zones (6-7). However, being that titanum is indigenous to Sumatra and adapted to a lowland, equatorial climate, it would not be realistic to expect it to survive planted outdoors in a zone 5 climate. There is no need to do the cold hardiness experiment in this case, but if you want to get rid of the titanum, I do believe that a number of people would be willing to buy it off of ebay.

It depends on how you're going to overwinter them. If you want them to continue blooming, then around 40 will be the cutoff. I don't care if mine go dormant, so I wait until it gets around freezing. Barb

Hi Purple. Yeah you basically got it right. Yes, the bloom on old wood. Dwarf Singapore Pink would be an excellent plumeria to start with. In zones 9 and above it would remain evergreen and probably bloom most of the year. I have one now that I got from Stokes Tropicals probably 4 years ago now. That tree is huge now! It easily has grown 20+tips so yes, it has the potential to bloom on all those tips. To me, the fragrance is really nice. I think DSP is over looked by many because it doesn't produce the huge flashy flowers. The flowers are just a soft pink but they still are pretty. I live in zone 6 and even my DSP is basically evergreen. It dropped all its leaves, and in the same month it grew all new leaves. Within another month or so, it will be blooming again. It has been the first tree to flower for me out of the 150+ trees I have. Another excellent variety for people just starting out would be Celadine. It's a very fragrant variety with yellow and white flowers. It's also a very reliable bloomer. You seem to have a pretty good idea on the concept of there temp requirements. I encourage you to read up on the older posts regarding there cultural requirements. I wish you the best of luck starting out with these tropical gems! Just one word of caution. THESE TROPICAL FLOWERING TREES ARE VERY ADDICTING!! I should know. When I was first getting started, I bought 3 unrooted cuttings. I was so proud of myself for getting them to root, I ended up with around 50 more before the end of that year! Andrew