What you have will work, I use it all the time. However if you refresh with f5 or hit the /home URL directly it will be null. This is because Flash Scope supports only one redirect and its attributes are automatically cleared after redirect.
If this is for a post redirect get
pattern then that is kind of important. Since both these handler methods are in the same controller you could get away with just using @SessionAttribute. The approach you are using will work as well but you will have to do something like this to handle the cases I mentioned.