Taishan Yellow Marigolds have huge tightly petaled blooms that are 3 inches or more across.  If you want a strong Marigold then, Taishan is the one for you.  These dwarf African marigolds have shorter peduncles (the part of the stem directly below the bloom) and thicker stems which make them sturdier.  Color is continuous because the secondary blooms come on even when the first blooms still look good.