The lettuce I'm harvesting for salads this year has been growing virtually wild and almost ignored in my garden for the better part of a decade, reseeding itself the whole time.

Well, they turned out to be wild lettuce. It might be one of a few wild species. ... Some common names include wild lettuce, great lettuce, prickly lettuce, bitter lettuce and opium lettuce.

Lettuce's bitter rival: Chicories. ... Though varied, chicories tend to be less improved and more like their wild ancestors. Their flavors are strong, often to the point of bitterness.

Q. What causes lettuce to flower, and why does it taste bitter after flowering? When an annual (or biennial) reaches the end of its life, it wants to reproduce.