Pertinent morphological details are given here, see if you can tell from these descriptions:

Tsuga heterophylla (western hemlock) description (conifers.org)

Tsuga chinensis (Taiwan hemlock) description (conifers.org)

Otherwise - choosing only from these two kinds - western hemlock seems more likely just going by the general appearance. One thing I can tell for sure is that your plants badly need to be fertilized.

if western tends to have more of a “two rows of needles“ then I think it looks more like Chinese.

the main one in the picture may need fertilized, but the yellow one you can see to the right is actually just naturally that color. Has been since germination..even once fertilized..