Flowers

How to Grow Moss Rose (Portulaca): Planting, Spacing, Care & Bloom

Quick answer

Start indoors 4 to 8 weeks before average last frost (WI). Transplant or direct sow after frost when soil is warm. Alias: portulaca / rose moss —

Moss rose at a glance

PlantStart indoors: 8–4 wk before last frost; Transplant: last frost
SunFull sun; lean well-drained soil; drought tolerant (WI/NC).
FrostFrost-tender
SpacingThin for air flow; full sun spacing per seed packet.
Days to bloomBloom season June–Sept. (Purdue HO-80)
-9-8-7-6-5-4-3-2-1LF+1+2+3
■ Start indoors   ■ Plant out   ■ Harvest
Weeks relative to last frost (LF). Colored weeks show when our ZIP planner schedules each step.
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Updated

Moss rose / portulaca (Portulaca grandiflora). Alias rose moss. No separate /planting/portulaca/ URL.

Moss rose flowers
Moss rose (Portulaca grandiflora). Photo: Suyash.dwivedi, Wikimedia Commons, CC BY-SA 4.0 (resized).

Sourced from university extension guides. For dates where you live, use the ZIP planting planner.

Planting timing

Wisconsin: “Seeds may be sown directly in the ground or started indoors 4-8 weeks before the average last frost for earlier bloom… Because they are frost tender, wait until the soil is warmed and the danger of frost has passed to seed outdoors or transplant into the garden.” (Wisconsin moss rose) Purdue HO-14 lists 6 weeks mid-range. Planner: Start indoors last frost −8 to −4; Transplant / Direct sow last frost 0.

Depth and spacing

Low spreading succulent; NC notes poor transplant success if root-bound — handle plugs carefully. Thin for air flow; full sun spacing per seed packet.

Sun, soil and water

Full sun; lean well-drained soil; drought tolerant (WI/NC). Crown rot if poorly drained (NC).

Care

Deadhead to deter self-seeding (NC). Avoid overwatering.

Bloom

Summer heat bloomer; flowers often close in low light. Continues until frost in warm sites.

Pests and diseases

NC: aphids, slugs; crown rot if wet. Cultural drainage and sun first.

Related: ZIP planner · organic pest control

Frequently asked questions

When do I plant moss rose / portulaca?

Start 4 to 8 weeks before last frost indoors (WI); set out or direct sow after frost.

Separate portulaca page?

No — same plant;

Does it transplant well?

Can be finicky — WI allows transplants after frost; NC notes poor transplant if mishandled.

Sources