A four leaf clover is not a Shamrock nor does it symbolize St Patrick. St Patrick allegedly used the three leaf shamrock to illustrate the Trinity. A four leaf clover of course would not serve that purpose very well.
A shamrock, associated with St. Patrick's Day is not a 4 leaf clover and a 4 leaf clover is not a Shamrock! A shamrock has 3 leaves and this has significance both traditional and religious. 4 leaf clovers have nothing to do with Ireland or St. Patrick.