Moss rose (Portulaca grandiflora) — care & requirements

In short

Requires full sun — the flowers open only on sunny days.
Drought-loving and, thanks to its fleshy leaves, very resistant to drying out.
Light, sandy and well-drained soil; does not tolerate overwatering.
Blooms from June to September in a rich range of colours.
Grown as an annual, it self-sows and propagates easily from seed.
Ideal for rock gardens, dry banks, boxes and containers.

Botanical data

Family: Portulacaceae (Portulacaceae)
Height: 0.1–0.2 m
Width: 0.2–0.3 m
Habit: Creeping
Growth rate: Fast
Position: Full sun
Soil: Sandy, Humus-rich
pH reaction: pH 5.5–7.5
Moisture: Dry, Moderate
Bloom: June–September
Hardiness: —
Propagation: From seed, From cuttings

Characteristics

It forms low, spreading mats 10–20 cm tall. The cylindrical, fleshy leaves resemble small needles and store water. The flowers, 2–3 cm across, single or double, have silky petals in shades of red, pink, yellow, white and orange.

Growing and care

Watering

The fleshy leaves store water, so the plant tolerates drought superbly. Water rarely, only after the substrate has dried out — an excess of moisture causes rot.

In summer every ~7 days · drought tolerance: High

Fertilizing

Sparingly — on soil that is too fertile the plant runs to leaf at the expense of flowers.

once a month or less · słaby nawóz do roślin kwitnących

Planting

Light, sandy and very well-drained substrate; on heavy soils add sand or gravel.

Timing: after mid-May, once the risk of frost has passed · spacing 15–20 cm

Pruning

The plant cleans itself of faded flowers; excessively long shoots can be shortened to make it denser.

Timing: Requires no pruning. · Caution: There is no need to prune for winter — the plant dies off after frosts.

Companion plants

Good companions

Biting stonecrop (Sedum acre)Practical observation

A succulent companion for dry, sunny spots with identical soil and water requirements — together they form a colourful, drought-loving carpet.

Common houseleekPractical observation

Both species store water in fleshy organs and thrive in the rock garden and in the dry crevices of sunny walls.

Sweet alyssum (Lobularia maritima)Practical observation

A low, carpeting plant with similar sun requirements, excellent for edgings and dry borders next to moss rose.

Bad companions

Siebold's plantain lilyPractical observation

The hosta requires shade and constantly moist soil, while moss rose needs full sun and drought — their needs are extremely opposed and unsuited to a shared position.

The evidence level indicates whether the relationship is backed by research, observation, or gardening tradition.

Diseases and pests

Aphids

Small (1–3 mm) soft-bodied insects, green, black or pink, feeding in clusters on young shoots and the underside of leaves. They excrete sticky honeydew. The diagnostic feature that distinguishes aphids from other small sucking insects is the pair of siphunculi (tubular projections) at the rear of the abdomen together with a tail-like cauda; a single colony usually holds wingless forms (parthenogenetic females) alongside winged migrants that fly onto new plants in summer. In summer aphids reproduce parthenogenetically and viviparously over many generations, so the population builds up explosively; in autumn many species produce a sexual generation that lays overwintering eggs on the host, and host-alternating species move between a winter host (often a tree or shrub) and a summer host (a herbaceous plant). Feeding symptoms include curling, crinkling and distortion of young leaves, stunted growth, yellowing, and the shedding of buds and fruitlets. Abundant honeydew coats the leaves, and the sooty mould fungus that develops on it forms a black film which limits photosynthesis; the honeydew is fed on by ants, which in return defend the colony against predators. Aphids are also important vectors of plant viruses (mosaics among them), transmitting them from plant to plant even during a brief probing puncture.

Toxicity

For whom	Level	Notes
Humans	Mild	Contains oxalates; unlike common purslane (Portulaca oleracea) it is not grown as a vegetable and should not be eaten.
Dogs	Mild	Eating larger amounts may cause digestive-tract irritation from the oxalates.
Cats	Mild	—

History and origin

It reached European gardens from South America in the 19th century. Because of its modest requirements and colourful flowers, it quickly gained popularity as a plant for dry, difficult sites.

Uses

Excellent for sunny rock gardens, dry walls, border edgings and for boxes and containers on fully sunlit balconies. It performs well where other flowers suffer from drought and heat.

Trivia

The flowers close on cloudy days and in the evening, and open only when the sun is out.
The English name moss rose refers to the small, needle-like leaves resembling moss.

Frequently asked questions

Why are the moss rose flowers closed?

This is normal behaviour for this plant. The flowers open only in full sun and remain closed on cloudy days and in the afternoon. Simply give it the sunniest spot in the garden.

How often should moss rose be watered?

Very rarely. The fleshy leaves store water, so the plant tolerates drought superbly. Water only after the substrate has dried out completely — an excess of moisture is more dangerous to it than a shortage.

Is moss rose edible?

It should not be eaten. It is an ornamental species containing oxalates and should not be confused with the edible common purslane (Portulaca oleracea) grown as a leafy vegetable.

Sources

Plants of the World Online (POWO)Database (GBIF, POWO…)
Missouri Botanical Garden — Portulaca grandifloraInstitution / botanical garden

Edited by:Redakcja Atlas-Flora. Updated: 7/19/2026.

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Moss rose