My guess would still be rose of sharon. I'm not sure they have to be multistemmed, I had one that looked a lot like yours until I moved it to a sunnier spot and started pruning it so it would branch more. Rose of Sharon is the only one I know of that is deciduous like yours. However, there are LOTS of hibiscus varieties and related plants, it could be one of the really obscure ones.

I'm in zone 9a and my parents, who live next door, have a good sized patch of this ginger growing in their yard. It's growing under a sweet gum tree on the south side so they get part sun and part shade. The plants get watered by the irrigation twice a week and whenever it rains but other then that get no special treatment. They freeze back to the ground every winter but never fail to come back in the spring. Right now they are blooming. This is a pretty tough ginger that doesn't need any babying.

I'm carefully monitoring the plumies for any bugs but not seeing more than maybe a couple of scale here and there (not enough to be doing this for sure. I did see some black spots developing on a couple of the Aztec Gold leaves, but that's it. One of the inflos is still completely green so I'm hopeful! If the Penang peach leaves are not typical Penang peach leaves, can you post a photo of a Penang peach leaf?

Here's a mind-blower: I managed my first conos in the same pot they came in for about two seasons. This was before I understood how it was possible. The peat had become so hydrophobic that if you just water them the same way as you would in gritty mix (free flow, no soaking, once every two to three weeks or less), they will do fine. What led to the inevitable collapse was the accumulation of salts because you can't flush peat as easily as gritty mixes.I would have had to soak the peat, wring the water out, soak it again and so forth. Clearly not possible. I moved them out of the peat and they struggled for a year, I lost two of the four. On the third year, they were back in shape. Nothing happens with these guys that doesn't take a while to fix. Your repartee with them can take weeks to months.