Normally, Node-RED flows are stored somewhere in the filesystem, in a file named flows_XXX.json.
When running Node-RED on Bluemix where are they stored? This could be important if your node instance doesn't start anymore.
As described by Harald in a previous answer once you create an instance of nodered boilerplate it is bound to a cloudant nosql instance for data, instead of the classic json file: this because a file on the filesystem would be reset as soon as your application restarts, while a db service persists. So if you wish to retrieve your application flows once it isn't able to start anymore, you have to access the cloudant nosql dashboard and extract the data locally.