minecraft-assets/assets/minecraft/blockstates/chorus_flower.json

{
    "variants": {
        "age=0": { "model": "chorus_flower" },
        "age=1": { "model": "chorus_flower" },
        "age=2": { "model": "chorus_flower" },
        "age=3": { "model": "chorus_flower" },
        "age=4": { "model": "chorus_flower" },
        "age=5": { "model": "chorus_flower_dead" }
    }
}