Run macro when item from drop-down list is selected

I saw a similar posting asking a similar question, but didn't see what I wanted, so thought I'd try asking it this way.

I have a sheet with a drop-down menu where the user selects a plant from the list, which then populates data in a table for that specific selected plant. I then have the user hit a button to "update" which hides unused rows. I'd like the selection of the item on the drop-down menu to trigger the macro, so they don't have to hit the update button as well. I know it seems pretty simple to select the item then hit the button, but some users won't hit the button and then will wonder why they have extra rows showing up.

Thanks in advance.
David

I used a data validation list. I don't know what a combobox is.

Cell G4 in this particular spreadsheet.

So let's say on Sheet 2, I have the user select the plant. I want it to update things on Sheet 3, Sheet 4, and Sheet 5 (tabs). If I understand correctly, I put that macro (Private Sub etc) on Sheet 2, and have it call up the macros that update the other three sheets. On THOSE macros, I need it to go to those sheets then run the macro (right now, the macro doesn't tell it to go to another sheet because the button is on that sheet).

Assuming the above is correct, can I have multiple Call NameOfMacro lines right after each other for the three sheet updating macros?

They don't need to be done in any particular order.

<<<Are all of them Private and in different sheet modules? >>>

Until 10 minutes ago, I didn't know the difference between a Sub and a Private Sub, so the answer is no, not yet. It seems I need to make them all Private Subs, which if I understand correctly, means they will only run on that sheet.