Hello,
P. ionantha does go dormant. I think the confusion is will the tropical Pings, which when dormant produce succulent leaves. P. ionantha doesn't do this.
Temperate Pings are fairly difficult to pull through dormancy. These are the Pings native to the southeastern part of North America that I am talking about.
They are extremely prone to fungal attacks when dormant, due to various reasons.
P. pumila for example is a tough ping to grow as a perennial, and most likely is more or less a annual in habitat.
P. careulea- another difficult ping to get through dormancy, P. lutea is easier.
P. ionantha, P. Planifolia, & P. primuflora
These pings grow in a flooded habitat for most of the year, I mean under or in shallow standing water. While primulfora grows in shade, P. ionanatha & P. planfiolia often grow together is strong sun.
Of these P. primuflora is the easiest, and plantlets form at will.
Heres the problem with them. To really get them to grow well they must be grown very wet. Combine this with cool weather and bingo fungal problems with rot.
So the dormancy is not much, and easier for people in a warm southern climate, farther north these pings are a real bear. During the winter I dry the containers, and these 3 species are the only 3 I grow without drainage holes in the containers. So they are moist, more moist than a lot of dormant cp are kept at. The cooler the weather the closer you watch the moisture level.
In early spring (here its mid Feb) they will start flowering, some are confused and flowering now. Flood the containers with warmer weather and more instense sunshine.
P. careulea, P. lutea- keep almost dry and cool during the winter, then my March to early April they will start blooming and can be kept somewhat more moist with good light.
Take care, time to eat a turkey,
~ Mike