But actually there are different levels of shade.
Plants are sensitive to the degree of shade.
In a forest or very heavy planting of trees, there may be no sun reaching the ground at all. On the north side of a large building, no sun may ever touch the ground near that building. Under a tallish or smallish tree, there may be dappled sun and shade. On the east or west side of the house there may be a period of 4 to 6 hours of sun reaching the ground. Part shade is better for flowering plants than full shade.