I love the answer that William gave; creative thinking at its best.
It might be interesting to see a photo of the bed in question and its location near the patio. I have an idea but not sure it if would look good. My idea is labor intensive, involves removing all the clay soil, digging deep enough to allow drainage, installing an arbor which will prevent some of the harshest sun, refilling the space with proper medium and planting vining plants for the arbor and low growers beneath.
