When you buy dried/dehydrated, compacted bricks of sphagnum moss from gardening suppliers and stores, etc., is it supposed to be alive, and/or able to grow, upon rehydration? Or is it dead?
I bought some of this Brunnings brand, expanding sphagnum moss (not sure what species, possibly Sphagnum cristatum and/or Sphagnum subnitens), from the similarly named (but unrelated) Bunnings Warehouse. It is supposedly ★★★★★/AAA-grade New Zealand sphagnum:
I experimented with it in a bunch of different environments, including some living terrarium/vivarium type landscapes.
Basically, it looks like a sopping wet, dark brown/yellow, lifeless mess of decaying fern fronds and leaf litter, blending in the the soils and substrates, and eventually taking the shape of its container. I was expecting it to develop into a lush, living, upright, green blanket, or carpet of sorts; like this: