This is one of my adenium in training to become a bonsai in flower now - in the Asian/Chinese style, as Desert Roses are very popular there. This is an adenium obseum which is grown for it's thick caudex and gnarly exposed roots, as well as it's amazing flowers. This particular plant has blooms in the 3.5 to 4 inch wide size range which last for a few days per bloom. Other kinds like the adenium arabicum (especially the Thai socotranums) are grown less for their flowers, which are selected to be very small, but for their extra thick trunks and very low branching forms to be grown in somewhat more traditional bonsai styles. These are a close relative to the baobob tree but stay more a shrub size, easily drwarfed.
This particular cultivar is grafted (very clean) and is called 'Joy Rich'. Blooms open with yellow in the heart of the petals which begins to fade by the second day. While these do not have a woody bark (neither do baobobs) they are a succulent that produces a woody inner core over time as they age and can live for hundreds of years. Flowers can be single, double, or triple layered and are usually some form of pink. White, red, black, purple, and yellow are less common colors more recently developed through hybridizing selection of new cultivars.
I currently have about 300 of these, most of which are 2nd year plants grown from seed. I have imported these mostly from Thailand and Taiwan, including my few grafted cultivars which were sent bare rooted. Phytosanitary certificates are required to get them through US customs. There are a number of enthusiasts collecting and growing these in the USA but the trees do best if you can provide either long hot summers with winter protection, or grow them indoors in a sunny window or under high output lighting. Adeniums (Desert Roses) do not tolerate being wet when temperatures drop into the 50's but are easily over wintered dormant or semi dormant while dry, in the 40's or higher. These thrive in the deep South, especially out west such as in Arizona where Mark Dimmit (a leading US authority on Desert Roses) has long grown them.
If you do internet searches on 'adenium bonsai' you can see a wide range of adenium types grown in various styles. Typically they bloom in the early summer after breaking dormancy and can remain evergreen if 'winter' conditions are mild. Or they can be deciduous in climates where they need to go dry (dormant) over the winter months.