Moss Rose

Moss Rose (Portulaca grandiflora)

Portulaca, Sun Rose, Rock Rose

Full sun; dry to medium moisture, well-drained to sandy; thrives in poor, gravelly soil; intolerant of wet conditions; pH 5.5–7.0.

4–8 inches tall, 6–12 inches wide, spreading succulent mat; blooms June through frost with rose-like single or double flowers in red, orange, yellow, pink, white, or magenta; flowers open in morning sun and close in afternoon and on cloudy days; spreads by self-seeding in favorable conditions.

Propagation: direct sow after last frost, barely cover seed; germinates quickly at soil temps above 65°F.

Native region: Not native to Tennessee; ornamental introduction from South America.

P. grandiflora is specifically suited to the hottest, driest, most neglected spots in Middle Tennessee landscapes — sloped south-facing beds, gravel edging along driveways, rock gardens, and dry raised planters where other annuals fail. The succulent stems and leaves store water, providing drought tolerance that exceeds virtually any other flowering annual. Overwatering or heavy clay soils with poor drainage kill plants rapidly through root rot; this is the single most common failure mode in Tennessee residential plantings. Modern cultivars including the 'Sundial' and 'Colorblast' series remain open longer in overcast conditions than older types. No significant pest or disease issues in well-drained sites.