The plant family hypericum has more than 370 species that include perennials and annuals. St. John's Wort, commonly grown for its medicinal properties, is a well-known member of this family. Other members of the hypericum family, such as the Rose of Sharon, are grown as ornamentals. Hypericum blooms from May to August and produces bright yellow flowers. Collect the seeds when they ripen between September and October for replanting. Hypericum thrives in USDA plant hardiness zones 3 and higher.
Start hypericum seeds between September and November. Fill a seed-starting flat or greenhouse bed with damp seed-starting soil. Scatter the seeds onto the surface of the soil and cover with 1/4 inch of soil. Keep the soil around the seeds at about 50 degrees Fahrenheit; germination will occur in one to three months. Mist every other day with water to keep the soil damp.
Transplant the seedlings into individual pots when they are about 2 inches tall. Fill 2-inch individual pots halfway with potting soil. Work under the soil with a small trowel or seed transplant tool to lift out the seedlings. Keep as much soil around the roots as possible.
Place one seedling in each pot so that the base of the stem is level with the lip of the pot. Fill in the soil under and around the roots so that it stands on its own. Secure the hypericum seedling in the pot by pressing down gently on the soil around the roots.
Transplant the seedlings outside in the summer. Select an area that has light, damp soil and full sun to partial shade. Dig holes in the planting locations that are slightly larger than the pots the seedlings are in, using a small trowel.
Slide the hypericum seedlings out of the pots. Hold the pot in one hand and turn on its side. Hold your other hand around the stem of the plant to catch it when it comes loose. Gently squeeze the pot until it comes loose if the seedling resists.
Place one seedling in each hole so that the base of the stem is level with the surrounding soil. Push extra soil back around the rootball and press down firmly. Water the area until it is damp to the bottom of the planting hole.
Keep the soil around the hypericum plants damp with weekly or biweekly watering. In very hot, dry weather, daily watering may be necessary. The hypericum should thrive well on its own in damp, rainy climates.