modify texture in realtime

I am making a game about making the world more beautiful but for this I need to modify textures in real time.
Like flower did in fact.

I don’t care if it’s definitive in the file (I mean in the asset stored on the hard disk) I just want to change the data on the graphic card.

But I did not found any informations about how to write any information in material (it’s only aesthetic so I don’t care if there is synchronisation between Ram and VRam), so I’m wondering if it’s possible to write on the Textures from Materials.

if the solution need a texture (or any byte array) created in the material that still can fit to my problem (even if I don’t think that is possible either), I just need something that can be persistent for the instance of the level (again I do not care if it mean loose the change when you reload the level)

If I cannot, please help talk with me in this forum thread to help me find another solution