Larry, I used the weed eater on my chrysanthemums and that worked very well. But with the daylilies, each one has a plant marker that I wouldn't want to hit.
I 've pulled up a few markers and they are hard to get back in the ground, so don't relish the idea of doing that. I'll just keep clipping a few at a time as time allows. Like you, it is not feasible to mow the clumps.

@Deryll I think I would agree with you regarding the difference between "summer dormancy" and "summer stress". Prior to this year I have really not noticed plants going dormant during Summer months. They're usually growing well this time of year. I do have some alleged EVs and SEs, however those generally go dormant in late Fall or early Winter. I say "alleged" because I've never had daylilies stay green into the hard Winter months, like they seem to do farther South. All mine are completely dormant by late November.

We had several inches of snow just before Christmas, followed by a cold blast with temps to -9. When the snow melted, I still had a boatload of plants with green leaves still showing. Mind you, there will only be one or two short leaves on each plant. I don't really know if these plants are called "evergreen" or "semi- evergreen", and I guess it doesn't matter, because they are still hardy. The thing about daylilies is that there are so many variables, and confusing why some grow so well in some places, but not in others- even in the same garden.

I will say in Larry's defense that I have new plants that were purchased this year that are looking a lot like his stressed plants, and I generally have that problem every year with new plants. I will assume that the plants are reserving their strength until the roots have caught up. And when it gets hot and droughty, those plants look really pathetic. I actually think the hot temps and dry conditions are harder on the evergreen plants more than the dormant ones... but that is just from my own observations without any data to back it up. Sorry, but I haven't had a chance to read up on the links provided, and I am waiting for others who are a lot smarter than me to chime in. There is a chance that I could be totally wrong about the whole thing! LOL!

I have been reading this thread with interest. I have a few plants that look like Larry's. They have dwindled back and have just a few small leaves. I will go out and check again later, but as I recall these are mostly plants that lived in pots the past season and even bloomed in the pots. I assumed they would do better once planted in the garden, but maybe they need time to adjust. These include South Sea Enchantment and Inner Destiny. Neither of them bloomed at all this year. As Deryll suggests, maybe they need time to get caught up.

I have nothing that looks like the picture Deryll posted.

Most of my plants are growing fine and still have plenty of green foliage. I have pulled off a lot of brown foliage mostly to keep the beds looking neat, but I have not noticed more dieback than usual. Then again we have had a ton of rain this month. We got 4" in the past two days. I am more worried about rot than summer dormancy.

@DeweyRooter
I am concerned that heat stress may be a contributing factor to rot.

Yes, I am sure that it is. In fact I think it is probably the #1 factor.

Seedfork said: DeweyRooter
I am concerned that heat stress may be a contributing factor to rot.

I think you would have to be very careful about watering when it is hot and humid if the leaves are dying back. It's the leaves that use most of the water a plant takes up, so with fewer or no leaves then the soil will just stay wet and it would be easy to overwater. The dying back of foliage in summer dormancy in other plants is a mechanism to protect them from adverse environmental conditions.

@sooby
That makes sense, and helps to explain why rot seems to take place after a long dry spell followed by a wet period. It seems daylilies can be grown in water, but there seems to be something about being dry for a period then being overly wet for a period that for some reason triggers rot.

That makes sense to me, Larry, and that is why I am a bit worried. June was pretty dry here and July has been really wet.

I am not familiar with rot at all. I haven't ever had it here after 30 years. Must be a southern thing?

As a rule, I normally never lose any plants. I did lose a couple over the winter last year, but they were fully evergreen and just planted in the garden. I am often surprised that some I think will be extra tender turn out to be quite hardy, and those that are supposed to be very hardy for other people often struggle. Until last year, the only plant I ever lost was Max Factor. A good many were on the verge of death when I tossed them though.