I agree with the other PP, especially the idea of having a class “mascot” and watching the animal change throughout the seasons. I would not worry about it not being colorful- if it is interactive the kids with remember. You can add in the color with the flower seats you have as well as pictures of animals.
Kindergarten was my favorite year as a student and I had the best teacher. He was a big nature guy and his theme, naturally, was nature. He did a unit on the Great Kapok Tree and I remember it so vividly. (I was the anteater and had so much fun making the costume with my dad)
This teacher shaped my life and my world, and I never got to tell him that. I give so much credit to kindergarten teachers. I wish you luck in your new year!