Heat a small amount of oil in a pan over medium heat. Cook and stir onion and carrots in oil until tender.
In a deep pot, combine beans, carrots and onion, mushroom broth, bouillon, and bay leaf. Pour in water. Tie together parsley, rosemary, thyme, and savory, and add to the pot. Cook till beans are just cooked. Take care to not let them get mushy.
Stir in potato, and continue cooking for 1 hour. Remove herbs before serving.