Last week we took a look at the best new edible plants hitting the market in 2016. This week it’s time to see what breeders and growers have cooked up in the way of new and interesting annual flowers.

Roses are red, violets are blue. Except they’re not. They’re, er, violet. True blue flowers are exceedingly rare, and not for lack of effort. Plant breeders have repeatedly tried to nudge roses and ...