Q.I Want To Plant Flowers In My Yard. The Area Faces Northeast. Soil Is Decomposed Granite
What and how do I plant
Want camellias, azaleas, lilacs, maybe ferns???? Also hot hot in summer
Is it possible

Certified GKH Gardening Expert
If your planting medium is only decomposed granite, you'll need to amend it. This article will tell you what you'll need to make it viable for planting:
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/amending-sandy-soil.htm
Here are links to articles about the plants you describe. The ferns need a shady area to thrive. The lilac must be specific to warm regions; don't worry there are plenty to choose from. The camellia and azalea need a shady to part shade location and they need acidic soil. Here is more:
https://www.gardeningknowhow.com/ornamental/flowers/camellia/caring-for-camellias.htm
Here's an article about growing flowers in full sun, and one about growing bulb plants in hot areas:
https://www.gardeningknowhow.com/ornamental/flowers/fgen/full-sun-plants.htm
https://www.gardeningknowhow.com/ornamental/bulbs/bgen/bulbs-for-hot-climates.htm