Candela wrappers are green on purpose. The leaf is cured with heat so that it dries before its chlorophyll breaks down. The result is a pale green to olive-colored wrapper that was once much more common on cigars sold in the United States than it is today.
The green color comes from the curing method. Candela is not a green variety of tobacco grown in the field; it is a way of curing the leaf. The flavor is often described as grassy or fresh, but these are common descriptions, not measured results.
Like claro and maduro, candela is a wrapper color you can recognize from across a shop. It describes the wrapper, not the cigar’s size (vitola).