to answer #80587 if I may:
Most molds and fungi (seen as fibrous white strings in the compost) associated with the composting process of organic materials are beneficial to plant life, if anything. The decomposing organic tissue of healthy tree leaves will eventually feed the plants they're mulching. About the only tree leaves not to use would be walnuts, they contain a growth inhibitor, and avocado, as they don't break down well.
Just don't smother the crown (the point at which the stems emerge from the soil) of the plant. Give the plant a few inches of breathing room all around .
The mulch will keep the soil cooler and more moist between waterings, and bonus: earthworms love leaves! Their manure is called earthworm castings and is highly prized by gardeneers for its rich content of humic acid. Plants love humic acid!
As far as your daylilies with marks on the leaves--it could be a symtpom of leaf disease brought on by our late spring rains. When the warmer air temps of late spring combine with extra moisture and humidity, it creates the perfect growing conditions for bacterial leaf spot diseases. Usually it's temporary; the warmer, dryer weather we're getting now should clear it up. Clean up your dayliles by removing the affected foliage and disposing of it. The new growth should come out disease-free. In any case, the leaf spot is tempory, cosmetic and not threatening the demise of your plants. Daylilies are drought tolerant; make sure you're not over-watering them and encouraging extra moisture to sit at the crown. Give them a bit of all -purpose fertilizer, organic preferred, and enjoy them.