In my area (9B, mostly) Hypericum calycinum will grow in sun or shade.
In a sunny location it requires regular water (we get no summer rain here). Even then it can sunburn.
In the shade it can get by with very little water.
Optimum way to grow it here:
Water through the summer.
Fertilizer (not much, but some)
Part shade from the hottest sun. Dappled light under trees is very good.
Mow it every year to every 3 years to get rid of the old, scraggly stuff and encourage new, lush growth. Mow it in February- the new growth happens in March.