I did find one website that noted 'Pink Pearl' was also used as a common name, but this specific cultivar seems to be a selection that was introduced by the Mt. Cuba Center.
I am so sorry that I am unable to answer your question. This plant is new to me, and I have no experience growing it. I just saw it growing at Mt. Cuba Center (https://mtcubacenter.org/) on a tour of their gardens.
You might consider contacting Mt. Cuba directly: [email protected] with your question.