I do not grow daylilies in my own yard, since I am more into succulents. But I see them in our common areas here.
Soil is heavily mulched here, to allow better moisture retention when the very long dry months come around. The HOA uses timed deep watering at night during the 6 to 7 months of zero rain fall and our humidity levels goes very dismal from 30% to 0%. Summer temps here hit a very dry 95F to triple digits for several weeks.
Then the mulch becomes protection for the base of the plant when it gets too cold at night in winter. Typically our overnight cold temps is around 30F to 40F, though there are times we do get some few hours of 20F to 21F. Every year is different, like this winter, we are more into rain, so it kept the areas overnight cold temps at the 30F to 40F range.
During Fall when blooms are over, the plants are trimmed down heavily, so it is bare during winter. If winter comes about rainy like it did now and not too cold overnights. the daylilies may send up new leaves right away. Our temps easily goes up anyways, so the moment daytime starts hitting 60F, these bulbs are quick to wake up, sending out their new leaves. Then by mid Spring it is the start of blooming time.
I see the gardeners apply some granular fertilizer in Spring, shaking them around the plants.
Our location is more inland, so our heat conditions during the dry months are more intense. It is different when these daylilies are in the Bay area, they have good coastal air influence, makes their bloom period much nicer and longer there with their pleasantly cool and sunnier conditions.
