@ Fury:
Oh, what happened to the beautiful plants I sent you!?! That U. sandersonii sheet was so nice...
Well, at least the U. longifolia is doing well!
Yeah, about that...
So the D. capensis was decimated by an aphid infestation. A few of them must have came over with the plant and multiplied like... well, aphids. I lost one of the plants before I could get rid of the infestation. So, I took some root cuttings and repotted the surviving plant. The plant was none too happy about the root cuttings, but it has since gotten over it. It's regrowing, although it looks like the growth is smaller (shorter leaves; smaller plant diameter) than it was when I got it. That plant will be fine; it's just been through hell and now has to recover. On the (very) bright side, I now have a dozen quickly growing plantlets that spawned off of the root cuttings. Its lineage will carry on!!
That D. aliciae - I'm still baffled by what happened. Most of them died completely, and after repotting them into fresh media and letting them dry out more often, I THINK I see some new growth starting to pop out of the blackened crowns. They currently look way worse than they did in the picture I posted... but I haven't lost hope yet.
Same goes for the D. venusta. I'm not sure what happened there.
Really I'm beginning to suspect the sand I was using in my soil. Perhaps I didn't rinse it well enough, but those plants that are more sensitive to minerals in the soil (especially D. adelae, which I killed several of) seemed to slowly decline and die. After repotting into a mix made with aquarium sand, the damage seems to have stopped. Hmmmm.
The U. sandersonii was indeed very nice. I think it wasn't getting enough water. Same with the U. longifolia. I've since put them in water that goes between half and two-thirds of the way up the pot. The U. longifolia seems especially thankful; I expect to see the U. sandersonii turn around, too. The D. spatulata growing in the U. sandersonii look happier; they're dewy and are sprouting new growth. One is even producing a flower stalk.
Can Utrics be overcrowded in a pot? Will leaves turn brown and die as competition ensues below the soil? That might be a possibility...
BUT, the Pings you sent me are THRIVING. They are the two happiest plants in my collection (the P. "Sethos" especially). The P. esseriana seem to be getting eaten by tiny little creepy crawlies. I'm going to re-pot and treat with neem soon.