South Carolina's Flag History
Asked by the Revolutionary Council of Safety in the fall of 1775 to design a flag for the use of the South Carolina troops, Col. William Moultrie chose a blue which matched the color of their uniforms and a crescent which reproduced the silver emblem worn on the front of their caps. The palmetto tree was added later to represent Moultrie's heroic defense of the palmetto-log fort on Sullivan's Island against the attack of the British fleet on June 28, 1776.
South Carolina needed a national flag after it seceded from the Union on December 20, 1860. The General Assembly considered a wide range of designs, but on January 28, 1861 added the palmetto to Moultrie's original design, thereby officially creating the flag as we know it today. A resolution proposing changing the color to "royal purple" as a memorial to the Confederate dead was resoundingly defeated in 1899, leaving the flag's Revolutionary War symbolism intact.
By statute the flag shall be displayed "upon the inside of every public school building in this State so that all school children shall be instructed in proper respect for the flag" and daily except in rainy weather, from a staff upon the State House and from a staff upon each County Courthouse. The State Flag is also to be displayed in accordance with rules set by the State Superintendent of Education, on the grounds of educational institutions supported in whole or part, by funds derived from the State. It is also prescribed that any person who mutilates, injures or desecrates the State Flag, wherever displayed, shall be guilty of a misdemeanor, punishable by a fine of not more than $100 or by imprisonment for not more than 30 days or both.
Link here to the South Carolina State Historical Society for facts, figures and history of South Carolina.