Yes, you can grow native plants but you will still need to loosen up the clay soil and find someone to donate you some compost, rotted leaves or old manure.  Hard packed clay soil often sprouts only "weeds" because these are the tough plants that have adapted to such difficult growing conditions. Poor drainage is the hallmark of clay soil and so Mediterranean herbs such as Rosemary would not do well unless you loosen up the soil. Sometimes a sign that says "compost needed here" can get someone to empty their compost onto the site. A lawn care company may have rotted grass clippings to offer for free. Maybe someone with old potting soil left in containers will allow you to reuse the potting soil in the site.  You do not say where you live but edible natives such as mahonia, salal or huckleberry could adapt to the difficult site. Keep growing, Marianne Binetti