Moss roses are succulents and do well in hot, dry climates. They are originally from Uruguay, Southern Brazil, and Argentina. There it grows on dry rocky slopes and plains. The flowers come in a variety of colors, including yellow, pink, coral, fuschia, red, and white. However, the flowers stay closed on cloudy days, only opening in the sun. Older types of moss rose open at noon and close at dark. Newer cultivars open early in the day and stay open all day.
This annual will grow in virtually all zones, from two to eleven. Its scientific name is Portulaca grandiflora. There are other plants that are sometimes called moss roses so the scientific name is important to make sure you are getting this plant, not some other one.
Moss rose is a low growing plant, growing from three inches to nine inches tall and six to twelve inches wide. It is a succulent, so the leaves expand when there is water available and contract when it is dry.
Moss rose only grows in the sun. It will not grow in the shade. It is usually seeded in the area where you want it to grow. You will need to prepare the bed for it by tilling to a depth of six inches and working in three inches of compost. Then spread the seeds on the prepared ground after all danger of frost is gone.
You can also start the seeds inside in beds then transplant the plants to individual pots when they become large enough to handle. You will need to prepare the bed the same way, but can dig a hole and put the moss rose in it, then fill it in. Water the transplant in. Plant seedlings twelve to twenty-four inches apart so they will have room to spread out. Transplants will get bigger than plants that are directly seeded since they have a head start on growing.
The moss rose blooms in the summer and early fall. It is self pollinating although insects may help with pollination. Be sure to pinch off spent blooms to keep it producing flowers.
The moss rose is a relative of purslane and the leaves are edible raw or cooked. So are the seeds. The root is edible cooked.
Moss rose is used to growing where it is hot and dry. It will grow in clay soil, but prefers dry sandy loam. It should be watered only when it starts to wilt. Otherwise it likes dry feet and can go a long time without water. It is very good for xeriscaped gardens and for lining sidewalks and driveways, where there is a lot of reflected heat from the pavement.
Moss rose does not require fertilization until mid summer. Then fertilize with a balanced fertilizer such as 10-10-10, following the package directions for amounts.
Moss rose is vulnerable to root rot nematodes and to aphids.
Moss rose will die at the first hard freeze. After that, pull the plant and toss it into your compost bin.