To make topping: In saucepan, combine rhubarb, orange juice and maple syrup. Bring to boil, reduce heat to medium and simmer for five minutes until rhubarb has softened and starts to break down. Add strawberries. Return to boil and then reduce heat slightly and cook, stirring occasionally, until strawberries have softened, and liquid is thickened, about 5 minutes. Remove from heat.
To make waffles: Preheat waffle iron to medium-high heat. In large bowl, whisk together all-purpose flour, whole-wheat flour, wheat germ, baking powder, baking soda and salt to combine. In another large bowl, whisk together yogurt, milk, canola oil, maple syrup, egg and vanilla. Stir wet ingredients into dry ones, mixing only enough to combine.
Spray waffle iron with canola oil cooking spray and ladle batter onto waffle iron according to manufacturer's directions. Close waffle maker and cook batter until golden brown, about 5 minutes. Repeat with remaining batter. Dust with confectioners sugar, if using. Serve with strawberry topping.