Alyssa, I am not an expert, but will give you some info based on what I have read and experienced.

There is a group that will group all Adeniums as 'obesum' and all the known species to many of us, just as sub-speices of the 'obesum'. I am not going to venture into this, as most being sold are sold by what we know as different speices.

The 'obesum' is the most recognized by many, as they produce the fancy blooms that you see. There is so much crossing being done that it is very difficult for anyone to give absolute authenticity of plant parentage.

Most of the Species names are given from the area or region in which they have been discovered or found growing natively.

Crossing of speices is and has been done very successfully, but not all species will cross, such as the true socotranum. Aslo, many Adeniums are not cannot be crossed as they are not fertile. Something that hybridizers know or learn as they proceed with their trials.

Whether one species is harder to care for may be an issue as to where you live and/or what conditions you can give.

Arabicums, TS, Swazicums are more tolerant of cold (not below freezing and wet) than Obesum.

I have most of the Species and overall I treat them about the same. Mine are in for the Winter months and out all day late Spring - early Fall.

In my experience growing them. I would have to say that it is a matter of preference as to whether you want beautiful and large blooms with varying colors (obesum). If you prefer a very large caudex with a wide girth, then Arabicum.

Hope some of this helps.

Rick

Thank you, Rick! I keep seeing people on here posting pictures of different species/subspecies and aside from physical differences I was unclear on the rest. Maybe I will try Arabicum, I do love a nice fat plant!

Hi there! I've been absent from this forum for several months, but now that the weather is warming up and ski season is ending :-( I will probably be around some more.

A. Obesums are known mostly for their striking flowers. They have been bred to have almost every color imaginable. Usually they develop less of a caudex than Arabicum or Thai Socotranum varieties, which tend to have pink flowers only.

I'd say if you are mostly interested in the form of the plant caudex, you should look for Arabicum or Thai socotranum. If you are more interested in flowers you could get seeds (if you have a year or two of patience) or get some grafted plants.

Yesterday I repotted some of my seedlings that I planted in the fall. They've been cramped in very small germination containers, but should explode with growth this summer. This one is a 'Brazilian' arabicum from Mr. Ko's seed.

All of the broad-based Adeniums are Obesums. Arabicum and Socotranum are subspecies of Adenium Obesums. Note in the following reference how they do not drop out "Obesum" from the full name:

http://www.patiojewels.com/Types-of-Desert-Roses.html

I am looking for a better photographic reference for each of these subspecies, so if someone has a URL for such a page please post it.