Okay these plants usually look similar, one being smaller. This year the smaller plant refuses to completely leaf out. It made a few flowers but what the heck is wrong with it? No softness or signs of rot, just small leaves and few of them. Here is a side by side comparison.
All living under the same conditions. All but the pink grafted are species that I got when they were fairly small. I keep meaning to order another hybrid graft but haven't. I am stumped (no pun intended) on why this plant has refused to grow this summer. I can live without the few flowers that the other plants make but am worried the plant will die without leaves.
I have a similar situation here, equally confused by my Adenium this year. It has a few leaves and buds, so it's clearly awake, but not much is really happening. My current theory is that it's waiting for summer temperatures to arrive (it hasn't been much above 70°F for the past couple of months). Either that or I need to feed/water it more, but I'm not in a hurry to rot it out, so I'll just wait and see.
I have several adeniums that started to grow and got stuck in the small leaf level. They are in s/h so I think that may have something to do with it. But another (in s/h) is blooming like mad. We are plenty warm here and they all are side by side. I have been wondering the same about mine as you have about yours newtonC.
I wondered if it could be root bound. Maybe later you could check, although I have checked roots in the heat here in Phoenix on various plants without a problem. I just get it back quickly, not letting the roots dry out. But you have to do what you think best.