I planted sweet potatoes in one of my hugelsbeds last year. I have sandy loam soil and the beds were filled with wood.
My biggest problem growing the sweet potatoes was vole damage. Voles love hugel beds and have invaded my garden.
This year the sweet potatoes will be planted in a swale berm where I less of a vole problem.
Maybe it was because it was a new hugelbed and hadn't settled for a year or two, but I didn't get as many nice sized sweet potatoes as in regular spaded garden soil. I got one HUGE fibrous sweet potato each where they were transplanted and a few undersized runts when I rummaged through the rest of the hugelbed. Maybe that is what this particular type of sweet potato does when there is no soil compaction to grow against. This year I am back to growing sweet potatoes in the regular garden.
I'm discovering that success with sweets in any particular spot depends a lot upon the variety. Some produce almost all their tubers under the main plant. Others produce them spread out. Some will produce one main tuber then lots of little ones. Others have lots of medium sized ones. Some just make rounds. Some thin and long. Some produce in semi shade. Others need full sun. Some do better hot and on the dry side. Others can do well with cooler temps and plenty of rain. I haven't figured them all out yet but I have noticed wide variations between varieties.
I have an orange type that is a semi bush and produces all it's tubers under the mother plant. It's my best one for hugel beds. It is some sort of commercial type. But many of my others don't preform well in the hugels. A white one (an old hawaiuan variety) I have produces great in a confined grow box but terrible out in the field. When grown under dry conditions it makes just one giant tuber. When things are moist, it makes lots of medium sized, good flavored sweets. I'm growing two yellow types that are only average producers but one does best in semi shade, the other requires full sun in order to make tubers. Gee, varieties can vary widely.
Even when I try to prepare a consistent bed for them, I can see a big difference in the harvest from year to year. So I'm assuming the weather has a big effect. How much sun vs cloudy days, how much rain and the frequency, how much dew, wind, etc. I had a year of super abundance once and haven't figured out exactly why. When I tried to replicate it, the harvest wasn't the same.
All I can say, I'd give it a try. But with sweets, it may be best to plant them in a couple of different spots to give you the best chance if a good crop.
It's never too late to start! I retired to homestead on the slopes of Mauna Loa, an active volcano. I relate snippets of my endeavor on my blog : www.kaufarmer.blogspot.com