Leis on the King Kamehameha statue in Honolulu; photo by Daniel Ramirez on Flickr (use permitted with attribution).
Official Island Colors of Hawa'i
In addition to having official island flowers or lei materials, each Hawaiian island also designates an official island color:
Hawai'i: ‘Ula‘ula (red) - island flower
Maui: 'Ākala (pink) - island flower
Kaua'i: Poni (purple) - island lei material
Moloka'i: 'Ōma'oma'o (green) - island lei material
Lāna'i: 'Alani (orange) - island lei material
Ni'ihau: Ke'oke'o (white) - island lei material
Kaho'olawe: Hinahina (silvery gray) - island lei material
O'ahu: Pala luhiehu (golden yellow) or melemele (yellow) - island flower
Source