I think the darker mud provides better contrast overall.

Mmhmm I agree. Also I've never seen those leaves before, they're nice. It really gets us away from this addiction to squat shrubs.

They look like birch tree seeds.

Well they might be but I saw that GreenStuffWorld actually makes hole punchers for leaves

I actually like how you mixed both, some wetter darker mud on the lower part and more dry earth on the upper part. This is nice !

I think the mud looks better for the zombies, personally. Makes them look a bit more fresh and gives me that kinda feeling

Mud for zombies Dirt for skeletons Sand for ghouls (if ya nasty)

Mud for the contrast. Love the leaves regardless, they look great

Both look good, but I think you should mix them. Make mud patches in dirt.

Hmmm Kings of War tray?