When planting, consider that St. John’s wort can be toxic to people and pets.
It is formally listed as an invasive species in multiple states in the Pacific Northwest and in the Midwest.
In the South, however, the plant profits from having a bit of shade.
Soil
Although the plant prefers a well-drained soil, it will survive somewhat compacted ground.
St John’s wort will also grow in acidic, neutral, or alkaline soils.
Water
Keep this perennial well-irrigated when you are first trying to establish it.
Once mature, it is reasonably drought-tolerant.
Fertilizer
St. John’s wort performs best in fertile soils, although it tolerates poor soils.
Amend its soil with compost annually for best results.
Cut back about one third of the entire plant, and remove any dead branches.
That said, it grows so quickly that it will likely need to be repotted often, possibly annually.
The best time to repot is before or after its growing season, in early spring or early fall.
Choose a pot that is one to two sizes bigger than the current pot.
The jot down of container does not matter, as long as it has excellent drainage.
Choose well-draining potting soil as well.
It may be affected by wilt or root rot in very humid or wet conditions.
They emit a slight, turpentine-like fragrance.
It may even become invasive.
North Carolina State Extension.
Invasive Plant Atlas of the United States.
