I am really surprised that 'Primal Scream' grows large fans, and forms clumps quickly. It is a runt in my garden, and has shown no signs of increase in two years. That gives me hope anyhow that in time it will do much better, it was about to go on my new list I made for culls.
This is what it looks like here after two years.
I thought of you when I was writing the post
. At one time, before you had seen the plant bloom, I thought you might have acquired the wrong plant. But then you posted photos of the bloom and it looks correct. I can't explain why yours and my plant grow so differently. Clearly they have been. Mine has been a steady increaser from the beginning and, in turn, those fans send up scapes the following season. I once remarked on this forum somewhere that I thought it was awarded the Stout medal as much for its foliage as for the bloom :). My conditions here are likely different in some big ways from yours. I probably tend to have a few lower temperatures during winter, though mostly I wouldn't think our winters would be significantly different. Summers, though, are going to be different. For plants of most any kind, summers here are harsh. High temperatures, lower humidity often aggravated by windy conditions. Night time cool off probably isn't the best for either of us - meaning temps stay warm at night. Your plants surely get more natural water via rain. Soil is different, I think. I grow mine in large containers and PS is in large clay-type container and so it's not garden soil. Generally I think plants grow better in the ground than in containers, but the daylilies in general seem to manage being container grown pretty well. It might be that PS requires better than usual soil or the spot it's located has something in the soil affecting the roots which is being seen in the fan growth. Do daylilies suffer from nematodes or some other soil pest? Grub worms? I've found grub worms in the pots when I've upsized or replenished the soil. I didn't see damage, but they were fat and healthy so they were eating something. Do hems get virus? If there is a plant virus that they can get, an infected plant might perform quite differently than one with no infection. I've wondered about the fading away of plants that start out growing well. It's a scenario that gets posted about plants growing in different locations and is usually applied in a dormant vs evergreen evaluation. That sounds like sickness to me, so I wonder if the wrong cause is being associated with the phenomenon. Just some random thoughts going on. Needs some science