Pelargonium sidoides
Pelargonium sidoides
South African geranium
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Taxonomy
Family Geraniaceae · Genus Pelargonium
Description
A compact South African pelargonium with velvety silver-green leaves and elegant, near-black flowers that bloom for months. It loves bright sun, dry, sharply drained soil, and makes a standout container or rock-garden plant with very low water needs.
Common Names
South African geraniumAfrican geraniumUmckaloaboBlack pelargonium
Context
nativeRegion
Grasslands and rocky slopes of South Africa and Lesotho.
usdaZones
9-11
companionPlants
Lavandula (lavender), Thymus (thyme), Santolina, Delosperma (ice plant), Sedum, Artemisia
culturalUses
Grown ornamentally for long-lasting, dark flowers; roots used in southern African traditional medicine and in commercial umckaloabo extracts for respiratory ailments.
Care
Care Requirements
LightFull sun to bright light; in hot climates, give morning sun with light afternoon shade.
WateringWater thoroughly, then let 50-75% of the mix dry. Reduce in cool months. Avoid waterlogging; very drought-tolerant once established.
SoilVery well-drained, gritty mix (cactus/succulent mix with extra perlite/pumice); neutral to slightly alkaline pH.
FertilizerLight feeder. Apply a balanced, dilute fertilizer every 4-6 weeks during active growth; pause in dormancy.
HumidityLow to average humidity with good airflow; avoid persistently high humidity.
TemperatureIdeal 60-75°F (16-24°C); tolerates 50-85°F (10-29°C). Protect from frost and prolonged temperatures below 40°F (4°C).
Growth & Life Cycle
HabitLow, clumping geophyte forming a basal rosette of velvety, heart-shaped leaves with wiry flowering stems.
Mature Size6-12 in tall, 12-24 in wide (15-30 cm tall, 30-60 cm wide).
Growth RateModerate
BloomingProlonged flowering in cool to mild conditions; typically late winter through summer in mild climates, with dark maroon to near-black blossoms.
DormancySemi-dormant in extreme heat or cold; semi-evergreen in mild, frost-free conditions.
Propagation
MethodsStem cuttings (softwood/semi-ripe), Seed, Division of multi-crown clumps
DifficultyEasy to moderate
Best SeasonSpring to early summer for cuttings; sow seeds in spring (late summer also possible in mild climates).
Maintenance & Notes
PruningDeadhead spent flower stems to extend bloom. Lightly trim leggy growth in spring; remove yellowed or damaged leaves.
RepottingRepot every 2-3 years or when rootbound into a wide, shallow container with fresh gritty mix.
Pests & DiseasesWatch for aphids, whiteflies, spider mites, and caterpillars. Ensure airflow to prevent botrytis and rust; avoid overwatering to prevent root rot.
ToxicityMildly toxic to pets if ingested (GI upset, drooling, dermatitis). Sap may irritate skin; generally not for consumption.
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