youth, growth, spring, jealousy.
Green!
Saint Patrick's ministry was in Ireland, and Ireland is known for its green landscape. Green is the color of Ireland (often called "The Emerald Isle"), the color of shamrocks, the official "Irish" color, as it were.
White is most often associated with Shinto.
No one specific color is ''sacred'', however the color most often associated with Muslims is green, because the Ottomans, who used it in their flag, were primarily Muslim.
The color yellow is often associated with fear or being afraid.
red is a color associated with power and strengh very often