I have planted last autumn a daffodils bed in front of my house. It is a full sun location.
Now it is all in bloom and beautiful.
This spring I bought some daylilies (happy returns and pardon me) and I would like to plant them amongst the daffodils.
I did not find so far any information about how to plant daylilies in an existing flower bed, and any advice would be highly appreciated.
I have attached a picture with my daffodils bed.
I would say that it would partly depend on how closely planted the daffs are. Mine are in clumps and about 7 inches deep or so. There is some room between the patches of daffs to add in another plant. I wouldn't plant any daylilies directly on top of any bulbs. Daylilies form long tuberous roots and may become to thick a cover for any daffs to punch through in the spring especially once the daylilies become established.
You will likely dig up some daffodil bulbs as you plant the perennials (by the way, there's no reason to stop at daylilies...), but all you need to do is to replant the bulbs. If you slice through any bulbs, just replant them too... there is a possibility that they will survive and depending on how the pieces were cut, may even produce a new bulb.