Know for sure? I'd need to be a geneticist I think, to answer that, so...
According to all of the research I've done, and after asking on this forum, other forums, and various FB groups occasionally, there has been nothing offered to refute the information in this article:
http://australianportulaca.blo...
The article explains that for about 20 yrs, P. umbraticola plants were sold as/labeled as P. oleracea cultivars, a misconception that persists.
There does seem to be some cultivars of P. oleracea, but not in regard to ornamental blooms, but in regard to culinary aspects, although it's difficult to know if the authors of articles about this kind of thing are using the botanical epithets correctly.
If there are ornamental cultivars of P. oleracea, with blooms larger than approx. pea size, I've seen no evidence of it.
Since so many people mistake P. umbraticola for P. oleracea, and continually comment about its' deliciousness as well as its' ornamental value, and it was sold with that name for so many years with nobody from the crowd that values the edibility raising a fuss, it seems edible, but I can't say that I've tried it. It's much more valuable to me as an ornamental. If it ever grows more than it has in the past and there is excess, I would satisfy epicuriosity. The last time I even saw any for sale was 2013 or 14. There are tons of recipes out there.