St Patrick used to explain the trinity ... the Father, Son and Holy Ghost (Holy Spirt)
No they are associated with Ireland
The shamrock is often associated with Ireland though it is the harp that is the official emblem of Ireland.
The shamrock.
The Republic of Ireland.
Thistles do grow in Ireland, but the thistle is most generally associated with Scotland. The plant associated with Ireland is the shamrock.
Tom & Jerry aren't directly of even indirectly associated with any specific holiday.
The rabbit is associated with the holiday, "Easter". This is because in the spring time, many animals are born -- especially rabbits.
thanksgiving
valentines day
Shamrock, Wisconsin Shamrock, West Virginia Shamrock, Virginia Shamrock, Texas Shamrock, Pennsylvania Shamrock, Oklahoma Shamrock, New York Shamrock, Colorado Shamrock, Florida Shamrock, Georgia Shamrock, Illinois Shamrock, Louisiana Shamrock, Missouri
shamrock
In Ireland, "the wearing of the green" meaning to wear a shamrock on one's clothing was seen as a sign of Irish pride or loyalty to the Roman Catholic faith. St. Patrick used the shamrock, a three-leaved plant, to explain the Holy Trinity to the pre-Christian Irish. The wearing of shamrocks became a feature of the saint's holiday.