I have the problem that I accidentally entered a command. That was a Gamerule command and as a result trees no longer grow and I can't use bone meal either.
And what's your question?
As the command is called
Have you set the TickSpeed or the RandomTickSpeed to 0? Open the chat and press the key with the up arrow until you have reached the command.
I set the Tickspeed to 200 and it didn't work. It was a day ago that I only noticed today
You have probably set the Tickspeet to 0, then nothing grows anymore. If it was really a / gamerule you will find a list here