Several species of plants belong to the genus Hypericum. One of the common members is called St. John's wort, or Hypericum perforatum. It is used in herbal formulas to help alleviate mild to moderate depression, according to Christopher Hobbs.com. Other species include Aaron's beard and Rose of Sharon. The Hypericums do fine in areas with hot, dry conditions and poor soil. All plants in this genus have yellow flowers that rise above the shrubby foliage on spikes up to 3 feet tall. All Hypericum plants grow from seeds scattered in fall or early spring.
Prepare a planting area in fall or winter by weeding the area and then raking it level. Hypericums prefer well-drained soil that is slightly acidic, but because many are considered wildflowers, they are not fussy about where they grow, so you needn't amend the soil before planting.
Scatter seeds of your chosen Hypericum species in the area you prepared in fall or early spring. Lightly cover the seeds with a thin layer of soil. You can also begin seeds indoors in flats in winter, about two or three months before your final spring frost.
Water the planting area thoroughly by running a sprinkler for about 30 minutes. Keep the area damp until germination occurs, which can take from three weeks to three months.
Prune established plants in spring to encourage the maximum number of flowers. If your plants become crowded, you can divide them in fall after they finish flowering. Every other year, cut your Hypericums back to the ground.
Purchase bedding plants of ornamental Hypericum species, such as Hypericum calycinum, which grows to 12 inches tall with a spread of 24 inches. It has many 2- to 3-inch yellow flowers with five petals. Plant after your final spring frost in a sunny to partly sunny area, and keep watered during dry periods. This plant makes an attractive, successful ground cover that does well under shallow-rooted trees.