I'm sure they can be grown hydroponically, but I can't think of any advantage in doing so. Here is an excellent page on growing Adeniums with a few surprising points for some, namely that these should be treated more like tropicals than succulents.

Adenium Culture: Producing Large Specimens Quickly

I have grown the desert rose in semi-hydroponics for many years. A big advantage to the s/h is the plants are much less prone to rot. I have never lost one and I have about 8. I keep them watered all year long. They also seem to grow faster as the roots are free to roam. The roots will grow right into the water and live very happily like that. I have about 90 plants in s/h and just love it. I tend to overwater and you can't do that with s/h.
{{gwi:471631}}

they do like a lot of water in my experience. And as much sun as they can get. Keep us posted.
Tally HO!

sallyo2, semi-hydroponics,that's interesting.could you explain how you do that,I'd like to try it on a desert rose joe

semi hydroponics are basically plastic containers that have 2 holes in the side about 1" from the bottom. The container is fill with Primeagra or clay pellets. You keep the bottom reservoir filled with water. I have been using it for about 8 years with great success.
{{gwi:471632}}

Hi Sallyo2
Sorry trying to understand the semi hydroponic idea when you say bottom reservoir filled with water do you mean the last inch of the container or to what level of the bottom of the container would you keep the full of water.
Cheers Maria

the holes you put in the container will regulate the amount of water that is held below them. all the excess above the hole will drain out.

Hi sradleye
After talking to my husband about Hydroponically growing Adeniums as he worked for many years in a local Hydroponic Nursery, I decided to give it a go. Flood and Drain is the method I have chosen and they look happy after a month of twice a day quick drink with nutrients added to the water. The medium I have chosen is clay balls nice and clean. They are still in full sun have a quick drink for about 10 min twice a day and I only used the plants I was sure would have died of collar rot or root rot and I am very happy with this method so far.

A photo taken when I first started

Photo just taken today looking good.

Maria, are they in pond-baskets/net-baskets only? And then you fertigate them twice a day? Do they ever sit in water?

Josh