Under both English and Scottish Law coats of arms belong to INDIVIDUAL PEOPLE NOT LAST NAMES!!!!!!
Do not be fooled into purchasing something with the "Pearson Coat of Arms". It is not legitimate. As a matter of fact these companies can only sell this crap outside of the UK. Under UK law they would be prosecuted and put in jail.
This family has not been granted a set of arms, as far as I can tell. It has used an assumed arms while in Canada. These arms are not legal so I will not reveal them until they bear legitimacy.
Again please check out the College of Arms for England. They have a great website that explains all of the rules that are associated with English arms.
There is a registered Scottish tartan for Pearson. It was created long ago by a Pearson from Cumbria. It's registry number 1734. It exists as both green and blue. This is the Tartan of this family.
This is the Official Pearson Tartan. It is registered with the Scottish Tartan Authority.