If using fresh ears of corn, remove husks and silks; rinse corn. Cut kernels from cob. (You should have 1 cup of kernels.)
In a medium saucepan combine fresh or frozen corn kernels, onion, vinegar, honey, chopped serrano pepper, salt, and cardamom. Bring mixture to boiling; reduce heat. Cook, uncovered, over medium-low heat for 4 minutes or until corn is just tender.
Remove from heat; cool slightly. Stir in jicama. Cover. Chill at least 4 hours before serving. (Store in refrigerator up to 4 weeks.)
Just before serving, gently stir in blueberries. Serve with slotted spoon.