Hi, welcome to GoY, there appear to be several plants with the name pearl as their common name, I think my best guess would be, Exochorda, common name pearl bush, try looking at Exochorda x. Macrantha 'the bride' , see if that is what you're looking for, Derek.

There is an Achillea plant called 'The Pearl' which has small white flowers.

Then there is the wild flower bachelor's buttons, called pearly buttons where I came from as a kiddy.