Moss rose (Portulaca grandiflora) is a succulent annual that is native to South America. Dr. John Gillies collected the first moss rose seeds in the 1820s in Argentina and brought them back to Europe. They have been cultivated into different varieties ever since. Moss rose is an old-time favorite with gardeners wanting an easy-to-grow, flowering annual that gives rose-like blooms. Moss roses come in every color except blue. Considered a ground cover, moss rose only reaches a height of 4 to 6 inches.
Wait until the weather has warmed before placing moss rose plants or sowing seeds into the garden. Plant moss rose when all chances of cold weather have left your region, as moss rose is a heat-loving annual.
Select an area in your garden to grow moss rose that receives full sunlight during the day. Grow moss rose in areas that receive high light because it will not perform well in shaded areas.
Grow moss rose in an area in your garden that is weed free and drains well. Moss rose will not tolerate soggy conditions and will not grow well if it has to compete with other vegetation growing in its space.
Space moss rose plants 8 to 16 inches apart to allow adequate room for the plants to spread. Moss rose can spread anywhere from 8 to 12 inches. Dig a hole that is a little larger than the plants root ball, but no deeper, to plant moss rose plants. Pack soil in around the plant, once inserted into the planting hole.
Amend clay soils, or soils that have a tendency to retain water, with sand. Work the sand into the soil to a depth of one foot. Amending sandy soils with compost is not a requirement.
Grow containerized plants in a lightweight potting mix that drains well. Plant seeds an eighth inch deep and cover lightly with soil. Situate the container in an area that will receive full sunlight.
Water moss rose plants when the foliage begins to look like it will wilt. Water the plants approximately once per week, depending on your local weather conditions. Keep the planting site moist but not soggy until germination, when watering freshly planted seeds. Moss rose is quite drought tolerant.
Fertilize moss rose plants with an all-purpose, water-soluble fertilizer monthly. Use a 10-10-10 or 20-20-20 blend and spray over the entire plant.
Prune the seed heads off moss rose plants if it stops blooming to force the plant to produce new foliage and blooms.