Moss Rose

Moss rose (Portulaca grandiflora) is a low-growing annual with fleshy, narrow leaves. Its flowers come in red, orange, yellow, white and pink, in single, semi-double and double forms. Plants form a mat about 3 to 8 inches (7.6 to 20 cm) high. The blooms open in bright sun and close at night and on cloudy days.

The plant is drought and heat tolerant and comes from hot, dry plains in Argentina, southern Brazil and Uruguay.

Start seeds indoors 4 to 8 weeks before the average last frost for earlier bloom, or sow directly outdoors. Wait until the soil is warm and the danger of frost has passed before sowing or planting out, because the plant is frost tender. Sowing in mid-spring at about 55 to 64 °F (13 to 18 °C) and planting out after frosts is another approach.

Just barely cover the tiny seeds. Keep the soil surface moist and leave the seed uncovered by more than a thin layer, since light is needed for germination. Reported germination times differ: about 3 to 5 days at 71 to 79 °F (22 to 26 °C), or 1½ to 2 weeks.

Moss rose does not take well to transplanting, so handle seedlings with care. Thin seedlings to at least 3 inches (7.6 cm) apart. Plant in full sun, where it gets 6 or more hours of direct sunlight a day, in well-drained soil; it grows well in lean, sandy or rocky ground.

Pinching or deadheading encourages more flowers and reduces reseeding, and deadheading also deters self-seeding. Richer soil and enough moisture give fuller growth and more flowers. Shear plants in midseason if they look straggly for a neater shape and fuller growth. It grows in pots and hanging planters, and it can trail over the edge of a hanging basket.

Aphids and slugs can occasionally be a problem. Stem or root rots can develop in wet soils, and poorly drained soil may lead to crown rot. Seedlings can be susceptible to damping off.

Moss rose will self-seed without becoming invasive, and it has escaped to naturalize on roadsides and in waste places in some areas. Deer do not favor it in most places.

The flowers are edible. The seeds can be eaten raw or cooked, although collecting enough of them for food is time consuming.