Java fern is readily available in shops round here anyway, but not Java moss for some reason, never been able to get hold of that. Java fern is the plant I have been most successful with (I do NOT have green fingers).
Bogwood you might want to soak overnight to get rid of some of the tannins. I boiled mine which got rid of a bit more. Then again, tannins are harmless, they just colour the water yellow. You probably want to give the bogwood a bit of a soak though to make sure it is clean.