I have three old hickory trees what grow under them like flower ect'?
Hickory trees produce the same toxin as walnut trees but to a lesser degree. The toxin juglone from these trees causes a dramatic wilting of susceptible plants. This article contains a list of plants that are not affected. https://extension.psu.edu/landscaping-and-gardening-around-walnuts-and-other-juglone-producing-plants
If you live in another region, search online for a list of juglone-resistent flowers in your state.