A beautiful and vigorous plant, the rose of Sharon can be started from cuttings, division, or from seeds. If you don't know how to grow rose of Sharon bushes from seeds, it may take a few tries to maintain moist soil, but starting the seeds is relatively easy. Gather seeds directly from the plant and sow right away or store in a cool, dark place until you are ready to grow your rose of Sharon bushes.
Fill pots with potting soil or a seed starter mix up to 1/2 inch from the rim of the pot. Place one seed in the center of each pot and cover with 1/4 to 1/2 inch of soil or mix.
Sprinkle a little milled sphagnum moss along the surface of the soil. This can help prevent fungi which otherwise thrive on damp soil.
Water the soil enough to make it moist, but not soaking wet or dripping.
Allow soil to dry a little before continuing to step 4.
Cover the moist pots with a seed tray cover or slip the pots into individual clear plastic bags. Set the covered pots in a warm location, with sufficient sunlight.
Keep the soil moist until the seedlings emerge, typically in about two weeks. Once the seedlings are out, remove any covering and place them in full sunlight or hang a grow light over your seedlings.
Harden off your seedlings outside once they are 4 to 6 inches tall and your region has passed the last frost of spring. Approximately two weeks of outdoor protection from direct sunlight, wind and weather elements should be sufficient.
Plant hardened seedlings to an area in full sun and well draining soil. Blooms can be seen from your seedlings as early as the next growing season, but they can take three to four years depending on the variety.