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Repotting guide

When & how to repot Moss rose (Portulaca grandiflora)

Also called moss rose, sun plant, portulaca, rose moss, eleven o'clock.

More about moss rose

About Moss rose

Portulaca grandiflora · also called moss rose, sun plant · flowering

Moss rose is a sun-loving, drought-tolerant South American annual grown for its jewel-bright single or double flowers in scarlet, yellow, orange, pink, white and bicolours above succulent needle-like foliage. It thrives in hot, dry conditions in poor soil and is ideal for sunny borders, rock gardens, containers and paving gaps. Listed by ASPCA as toxic to pets.

Mature size: 10-20 cm tall, 15-30 cm spread

Watch for — Root rot from overwatering: Portulaca is extremely sensitive to overwatering and soggy soil — the most common cause of plant collapse is wet roots, so ensure sharp drainage and allow soil to dry fully between waterings.

How to tell moss rose needs repotting

Repotting on a calendar is less reliable than reading the plant. For moss rose, watch for these signs:

For the underlying biology of a pot-bound root system and why it stalls a plant, see our guide to spotting and fixing a root-bound plant.

How often to repot moss rose

Every 2–3 years, into bone-dry mix. Moss rose's growth habit — low-growing trailing or mounding warm-season annual — sets the pace. Moss rose is a sun-loving, drought-tolerant South American annual grown for its jewel-bright single or double flowers in scarlet, yellow, orange, pink, white and bicolours above succulent needle-like foliage. It thrives in hot, dry conditions in poor soil and is ideal for sunny borders, rock gardens, containers and paving gaps. Listed by ASPCA as toxic to pets.

What size pot to step moss rose up to

Use a pot only one size up — or even the same pot with fresh gritty mix if the roots have room. Moss rose stores water and rots in a large pot of slow-drying soil. A tight terracotta pot that dries fast is far safer than a generous plastic one. Never up-pot a succulent by several sizes.

Not sure of the exact diameter? Our pot size calculator takes the current pot and root spread and tells you the right next size — it deliberately recommends a single step up, never a big jump.

The best time of year to repot moss rose

Spring or summer, while moss rose is in active growth and warm, is best — roots recover fastest then, and the plant is not sitting in cool damp soil. Avoid repotting a succulent in winter dormancy.

Step-by-step: repotting moss rose

  1. Repot dry. Do not water moss rose for several days first. Working with dry roots and dry mix dramatically lowers the rot risk for a succulent.
  2. Pick a snug, fast-draining pot. Choose terracotta one size up at most, with a drainage hole. Have gritty poor to moderately fertile, sandy or gritty, sharply drained soil ready.
  3. Tip it out and clean the roots. Slide the plant out, crumble off the old soil, and trim any black, mushy or dead roots with clean snips.
  4. Pot into dry mix. Set moss rose at its original depth in dry gritty mix, firming gently. Do not bury the stem deeper than it was.
  5. Wait a week before watering. Leave it completely dry and out of harsh sun for about 7 days so any damaged roots callus. Only then water lightly.

Aftercare

Keep moss rose completely dry and out of fierce sun for about a week so any nicked roots callus before they meet moisture; watering a freshly repotted succulent is the classic way to rot it. Then resume the normal lean, dry rhythm. Do not fertilise for about 3 weeks — fresh mix already carries nutrients and feeding freshly disturbed roots scorches them.

The right soil mix for moss rose

Moss rose wants poor to moderately fertile, sandy or gritty, sharply drained soil. Excels in lean, gritty, sandy or even pure sand soil where other annuals struggle. Rich, moisture-retentive soil produces lush foliage but few flowers and encourages root rot. Use a 50:50 mix of potting compost and coarse sand or grit in containers. Good drainage is non-negotiable. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting moss rose — frequently asked questions

How often should you repot moss rose?

Every 2–3 years, into bone-dry mix for moss rose. Repot moss rose every 2–3 years into a snug pot of poor to moderately fertile, sandy or gritty, sharply drained soil, ideally in spring or summer. Let it sit in dry soil and do not water for about a week afterwards so any nicked roots can callus. Over-potting and watering straight away is what rots succulents.

What size pot does moss rose need?

Use a pot only one size up — or even the same pot with fresh gritty mix if the roots have room. Moss rose stores water and rots in a large pot of slow-drying soil. A tight terracotta pot that dries fast is far safer than a generous plastic one. Never up-pot a succulent by several sizes. Use our pot size calculator to size it from the plant's current pot and root spread.

When is the best time of year to repot moss rose?

Spring or summer, while moss rose is in active growth and warm, is best — roots recover fastest then, and the plant is not sitting in cool damp soil. Avoid repotting a succulent in winter dormancy.

Should you water moss rose after repotting?

No — not straight away. Repot moss rose into dry mix and wait about a week before the first watering so any damaged roots callus over. Watering a freshly repotted succulent is the single most common way to rot one.

Should you fertilise moss rose after repotting?

Not immediately. Wait about 3 weeks after repotting moss rose. Fresh mix already contains nutrients, and feeding freshly cut or disturbed roots burns them. Resume your normal feeding routine once you see new growth.

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