growing flowers and trees on a river bank

[Moss Pecan Bottom]

:? We live on the river in Glen Rose so the only thing that really grows well in the soil is pecan trees. I want to plant my flower beds in something that can come back every year. The front of my home gets the West sun, and there is only one tree to shade it. The single tree leaves the South end flowerbed is always in its shadow. The North end one is in full sun.
In the Back of the house there is a Hill side on the river bank across the the river. So the morning sun is slow getting to the back and the afternoon sun has the shade of the house, after a certain time of the day.We also want to plant some new trees that grow fast and offers alot of shade fast, and can take the soil.