Use a block model for a plant

So, I want a block to generate only at the surface.

I tried hard with conditions but it did not work as I wanted.

So I figured out that plants do generate only on the sufrace.

With that being said, I remade my block to be a plant, and changed the bounding box and random model offset to be like any other block.

The issue now is that I want the texture to be like a block. I tried by uploading the minecraft base block.json :

{
    "gui_light": "side",
    "display": {
        "gui": {
            "rotation": [ 30, 225, 0 ],
            "translation": [ 0, 0, 0],
            "scale":[ 0.625, 0.625, 0.625 ]
        },
        "ground": {
            "rotation": [ 0, 0, 0 ],
            "translation": [ 0, 3, 0],
            "scale":[ 0.25, 0.25, 0.25 ]
        },
        "fixed": {
            "rotation": [ 0, 0, 0 ],
            "translation": [ 0, 0, 0],
            "scale":[ 0.5, 0.5, 0.5 ]
        },
        "thirdperson_righthand": {
            "rotation": [ 75, 45, 0 ],
            "translation": [ 0, 2.5, 0],
            "scale": [ 0.375, 0.375, 0.375 ]
        },
        "firstperson_righthand": {
            "rotation": [ 0, 45, 0 ],
            "translation": [ 0, 0, 0 ],
            "scale": [ 0.40, 0.40, 0.40 ]
        },
        "firstperson_lefthand": {
            "rotation": [ 0, 225, 0 ],
            "translation": [ 0, 0, 0 ],
            "scale": [ 0.40, 0.40, 0.40 ]
        }
    }
}

But the block is now invisible, and the hand texture is the same as before.

How can I use the built in "single texture" from the block for a plant ?

Thank you !
 

EDIT : I bypassed the issue by creating a new model in blockbench. This is not what I wanted but it works.