1) if you are going to try blueberries, wood ash kills them. My
raspberries take happily modest amounts of wood ash
2) other having covered pH concerns, I am assuming that Wisconsin has
moderately acid soil. In most cases flowers will appreciate a little
yearly application of wood ash. Flowers will not mind if you burned a
lot of funny stuff in your stove besides the wood,
3) some vegetables love wood ash, specially onions, beets, chard,
spinach, but also cabbage, carrots, lettuce and tomatoes like it. All
this from direct experience in my acid soil.
Wood ash should contain all necessary nutrients for growth (specially
the micronutrients except S, it is 50% Ca for example), except for
insufficient amounts of P, and no N. I use about two 5 gallon buckets
of wood ash every year, for about 1000 sq ft of vegetable gardening
space. I mix it in with perhaps two tons of organic matter of course,
and I add a bit of urea or high N/P grass fertilizer.