I have been planting perennials this week to fill in some of the gaps in my mulch beds and I still need to fill in a narrow strip of my landscaping where I don't have the ability to dig deep (due to large tree roots in the vicinity).

I am contemplating purchasing daylillies from Oakes (online) today. Is it too late for me to plant them for Zone 6A/6B (Northern NJ)? If not, should I follow any precautions to ensure they survive the winter? I've never planted daylillies so I would need any and all planting advice possible.

When I planted my other perennials (which are larger established plants) I use a mix of self-made vegetative compost, peat moss, and the native soil (all three in equal parts) to backfill the hole. Would I even need to do that for daylillies?