White Friday

Decorating the white tree, on Black Friday, gave Simmy the catchy blog title of White Friday which, of course, it cannot be because that would be the first Friday after Pentecost.
Why is it that the United Kingdom seems to be the only country that celebrates this holiday?
'Scholars' Walk' or Whit(e) Friday, carried with it a tradition... girls would have a new dress and boys would have new trousers.
Simmy remembered her mother sewing them new dresses for each Pentecost and now she finally knew where that tradition originated.