Because their size, population and importance to the Nation merited representation as full members of the Union.
Alaska joined the union January 3rd 1959 followed by Hawaii August 21, 1959. The first state to join the U.A was Hawai, Alaska joined a little later.
Um it is because the first king really liked the flower and declared that it be the state flower or else and nobody knew what or else meant
Both were US Territories.
Hawaii.