Daylilies are fully edible from the root to the flower. Most commonly (and most fun to use) the unopened flower buds can be used in stir fry, deep fried, or just tossed in a pan with other veggies. They are usually attributed to taste like asparagus with the texture and shape of okra. For a recipe, see below.
Caution: Not to be confused with tiger lilies or commercial lily varieties, some of which can be toxic. Most lilies are highly toxic to cats, and somewhat to dogs. A great start to identification is to look at the roots. Daylilies have fibrous roots with small nodules.
Remember: Harvesting or ingesting the wrong species of plants can have dire consequences, which is why experts suggest that you identify a plant based on three separate characteristics. Verify AT LEAST THREE between the fruit, stem, bark, flower, root, leaves, etc. Check here for an identification guide, and remember:
Never ingest or handle any type of wild plant without being certain you know what it is.
Any doubt, LEAVE IT OUT !