In a Dutch oven or soup kettle, saute potato, onions, carrot and celery in butter until onions and celery are tender. Stir in flour, salt and pepper until blended. gradually add broth. bring to a boil; cook and stir for 2 minutes.
Add asparagus; reduce heat. Cover and simmer for 20-25 minutes or until vegetables are tender. Cool to lukewarm.
In a blender, puree vegetable mixture in small batches until smooth. Pour into a large bowl; stir in cream and sour cream until smooth.
Serve warm, or cover and refrigerate for at least 2 hours and served chilled. Garnish with bacon, sour cream and asparagus tips if desired.