Portulaca grandiflora is commonly known as moss rose. Portulaca is a succulent plant with thick stems and leaves. The trailing stems reach 6 inches tall and spread 12 inches wide. The bright green leaves are cylindrical and 1 inch long with pointed tips. Moss rose blossoms bloom all summer with jewel-toned colors. These flowers only open in bright sunlight. When the light level is low, the flowers close up. Portulaca flowers are used as ground cover in dry, rocky areas. This annual is also planted as flower borders, container plants and hanging basket flowers.
Remove weeds, grass and debris from a planting area located in full sunlight. Even light shade will cause the portulaca flowers to close. Prepare the growing site after all danger of frost has passed.
Loosen the soil with a shovel to the depth of 6 inches. Break the soil clumps up and rake smooth. Portulaca grows well in poor, sandy or gravelly soil. Add a 2-inch layer of sand to the soil if it is heavy or clay. This will help with drainage problems and prevent root rot.
Mix your portulaca seeds with a 1/2 cup of sand to make it easier to scatter. Portulaca seeds are very fine and nearly impossible to handle. Carefully sprinkle the seed and sand mixture over the soil. Try not to create clumps of seeds.
Lightly rake the seeds into the soil with a hand cultivator. Do not bury the seeds deeply. The portulaca seeds only need a fine skim of soil on top to hide them from the birds.
Mist the planting area with a fine spray of water until the top of the soil is wet. The seeds will germinate in seven to 10 days with temperatures of 70 to 75 degrees F. Flowers will appear 10 to 15 weeks after planting.