command arguments in the actual text bar

in my mod, there are 4 new trees.
for debugging reasons I made a command that grows those trees on the spot.
the way this works is /grow kardario or /grow ligoda and so on
so in the procedure it just reads the command argument index like normally.
though my issue is that when typing the command in-game it just says 
/grow <(arguments)>

but I'd like all the possible options to pop up in a list like other commands in minecraft, but I wasn't able to find much of anything about this on the internet, and looking at the code I managed to change the thing it says to <tree name>, but not make it an actual list.