Ahha! I found it! Had to search your gallery to find this (Sprout Swarm). Anyways, you asked for a critique and I'll do my best. I've never seen this card series before so my comments might not apply but I figure I'll mention them anyways
The overall effect of this is fantastic! Your use of cast shadows and highlights seems very natural and realistic, and the whole piece has a very believable outdoory feel. You've also created a very accuate sense of depth, and in such a small space that is quite impressive.
The only thing I could suggest for this is to add a little more gnarly details to the vines/roots coming from the sprouts - at the moment they seem very smooth and almost tentacle-ish, rather than something natural like a root.
Otherwise I think this is very well done! You are a very talented artist Dan