You can. By creating a shortcut to Spore and then adding the phrase -state:FloraEditor you gain access. For example, the full shortcut path could be
"C:\Program Files\Electronic Arts\SPORE\Sporebin\SporeApp.exe" -state:FloraEditor
And then exactly like that, given that your Spore game was installed at that location. Similarly, you can access the Cell Editor by entering -state:CellEditor. Having Galactic Adventures installed may require you to change the pathname to "C:\Program Files\Electronic Arts\SPORE_EP1\Sporebin_EP1\SporeApp.exe", in order to match it to the new executable (Galactic Adventures) that the game now uses. To run the editor, simply double-click the shortcut. The game will now launch as the given editor. To boot the original game, I think you need to close the game, remove the '-state: ...' argument from the shortcut (or create a new one so you have separate shortcuts for the actual game and for the editors) and then restart the game. I'm a little fuzzy on that part, since I haven't used Spore in a while and haven't used the special editors since a longer time.