Three Potato Salad with Bacon

It ended in the the words, "with bacon" so I had to try it! 

This one came from a Reader's Digest magazine but I am not sure which month.  I tend to just tear out the recipes I want to try.

4 medium unpeeled red-skinned new potatoes
3 unpeeled Yukon gold new potatoes
1 large unpeeled sweet potato, halved
3/4 cup buttermilk
1/3 cup light mayonnaise
2 tbsp grainy mustard
2 tbsp white vinegar or white wine vinegar
1 tsp salt
1/2 tsp pepper
6 slices bacon, cooked and crumbled
4 green onions thinly sliced
3 tbsp chopped fresh dill

1.  Place new and Yukon Gold potatoes in a large saucepan; cover with salted water.  Bring to boil; reduce heat, cover and cook until tender when pierced with a fork, about 30 minutes. Drain and cut into bite sized pieces.
2.  Meanwhile, place sweet potato in a small saucepan; cover with salted water.  Bring to boil; reduce heat, cover and cook just until tender when pierced with a fork, about 20 minutes.  Drain, peel and cut into bite sized pieces.
3.  In a large bowl, whisk buttermilk, mayonnaise, mustard, vinegar, salt, and pepper.  Add potatoes, bacon, green onions and dill, folding gently to coat.  Cover and refrigerate at least one hour for flavors to blend.