About 8 years ago we planted day lilies under a split rail fence along the edge of our property. Against my advise for the last 2 or 3 years he has mowed the foliage down instead of letting it die back. His year, which has been an unusully hot and dry summer, they have produced very few flowers. Is the problem the weather, or cutting down the leaves? And is there anything we can do to try to bring them back or is it a lost cause?

They can be brought back if you protect them. Can you mulch around them and put some rock in front of the garden area?

I am pretty sure they will decline and at some point not come back. Unless they are the old variety that it is commonly referred to as ditch lilies that they plant along the roadside.

I always let the foliage die back then remove in the spring. It may be like tulips where the root needs the leaves to regain energy for next year. I have heard about them fizzling out but I split every other year and am on year five with plenty of flowers.

They may need to be divided. Wait until spring,cut away all brown and dead stuff then dig up and divide. Some of the large clumps I've used a hatchet to break apart. Day lilies are extremely hardy and it's hard to kill them. I ended up dividing mine very late this year, just before they flowered and the foliage took a beating but they flowered very well. I spread them out and gave some away and started two new rows in a new garden section. They are great filler and borders.