Identity & taxonomy
- Scientific name
- Curio rowleyanus (H.Jacobsen) P.V.Heath
- Family
- Asteraceae
- Genus
- Curio
- Order
- Asterales
- Wikidata
- Q2050648
- Senecio rowleyanus H.Jacobsen (basionym)
- Kleinia rowleyana (H.Jacobsen) Bertoloni
- String of pearlsen
- String of beadsen
- String of peasen
- Rosary vineen
- Rosenkransplantasv
- Perleplanteno
- Perlekransda
- Helmiköynnösfi
- Erbsenpflanzede
Southwestern Cape Province, South Africa (arid scrubland)
How to identify it
Growth habit. Trailing, ground-creeping succulent in the wild — strings root where they touch soil and form mats. Indoors the plant cascades from a pot or hanging basket, each thin string bearing regularly-spaced spherical leaves and occasionally rooting nodes.
Leaves. Leaves are spherical to sub-spherical, 5–10 mm across, pale grey-green, arranged along a thin flexible stolon-like stem. Each sphere has a translucent longitudinal line ('window') running along one side — a structural adaptation that lets light reach chlorenchyma deep inside the leaf while minimising surface area exposed to drying heat.
Flowers. Small, cinnamon-scented, brush-like white flowers 1 cm across with conspicuous pink stamens, borne singly on thin stalks. Flowering is common on mature plants after a cool dry winter rest — a simple cue most indoor growers accidentally provide by forgetting to water.
- Pea-sized spherical leaves — no other common houseplant has this shape at this scale.
- Translucent 'window' line on each pearl — visible when held up to light.
- Strings root where they touch moist soil, creating new rosettes along their length.
- Cinnamon-scented flowers are uncommon and diagnostic when present.
Commonly confused with
String of bananas
Elongated, crescent-shaped leaves rather than spheres. Same genus, same care regime — more forgiving of low light than string of pearls.
String of watermelons
Larger, ellipsoidal leaves (2–3 cm long) with vertical darker green stripes resembling watermelon rind. Same genus, same care regime.
String of nickels
Flat coin-shaped leaves, not spheres. A tropical epiphyte (Apocynaceae), not a succulent; requires higher humidity and shaded light.
Care
Light
Very bright indirect light; a few hours of direct morning sun is ideal.
String of pearls needs significantly more light than most aroid houseplants. Place within 1 m of a south or unobstructed east window, or directly in a bright west window (filter harsh afternoon sun in summer). Insufficient light produces stretched, thin strings with widely-spaced pearls and bleaches the foliage to pale yellow-green.
Seasonal: Nordic latitudes above ~55°N: a full-spectrum LED at 15,000+ lux for 10–12 hours/day is effectively required from October through March to prevent winter stretch and rot.
Water
Deep soak every 2–3 weeks; monthly in winter.
Soak thoroughly until water runs from the drainage hole, then do not water again until the top 2–3 cm of soil is completely dry and the pearls on the underside of the strings are starting to pucker slightly. Overwatering is the single most common killer of string of pearls — rot spreads from the soil up the strings within days once established.
Seasonal: Reduce to one light watering per month from November to February, when strings are barely using water.
Soil
Very fast-draining gritty cactus or succulent mix.
A mix of 1 part commercial cactus/succulent soil to 1 part coarse perlite or pumice and 1 part horticultural grit or coarse sand is essential. A shallow, wide terracotta pot dries faster than a deep plastic one and is the default commercial choice for a reason.
Humidity
Any — low humidity preferred.
Curio rowleyanus is a xerophyte and does best in dry indoor air. High humidity (above 60 %) combined with still air encourages fungal spots on the pearls and accelerates rot.
Temperature
13–27 °C.
Tolerates briefly warmer (up to 35 °C) and cooler (down to 5 °C) but never frost. A cool winter rest at 10–13 °C with sparse watering is the trigger for flowering. Keep away from cold window glass in Nordic winters.
Fertilizer
Dilute feed once in spring and once in late summer.
A balanced or low-nitrogen NPK at quarter the label rate twice a year is plenty. Over-feeding produces long, thin, weak strings with widely-spaced pearls — aesthetically the opposite of what the plant should look like.
Seasonal: Never feed in winter.
Pruning
Trim overlong or damaged strings; replant the cuttings to fill the pot.
Snip long strings back as needed. Any cut section is a propagation cutting — let the cut end callus for a day before laying on or inserting into fresh soil.
Repotting
Every 2–3 years, in spring.
Move into the same pot or a barely-larger one with fresh gritty mix. String of pearls prefers being slightly root-bound; large pots hold cold wet soil around minimal roots and cause rot. Shallow and wide is better than deep.
Laying cuttings on soil
easy~2–4 weeksThe easiest and most effective method. Snip a string 10–15 cm long, let it callus for a day, then lay flat on the surface of dry gritty cactus mix. Press lightly and lightly mist every 3–4 days. Strings root at every node in contact with soil and fill the pot quickly.
Stem cutting in water
moderate~3–6 weeks, often rots firstPossible but less reliable than the soil method — pearls tend to rot on contact with water. If using water propagation, suspend only the cut tip in water and keep the pearls above the surface.
Division
easy~Immediate — divisions carry existing rootsA mature plant in a hanging basket is usually many individual rooted clumps. Unpot, gently separate clumps with their own roots, and pot each into its own container.
Common problems
Mushy strings, collapsing plant
Symptom
Strings go soft and squishy, then translucent, and collapse within days.
Cause
Root rot from overwatering, cold wet soil, or a container without drainage.
Fix
Unpot immediately. Cut away any firm green strings with unaffected stems — these are propagation material. Discard the rotted mass and soil. Let the cuttings callus for a day, then lay on fresh dry cactus mix and start over. Recovery is possible but the original root mass is usually a loss.
Shrivelled, wrinkled pearls
Symptom
Pearls go from plump spheres to wrinkled raisin-like shapes.
Cause
Under-watering or a pot-bound root system unable to absorb what water it gets.
Fix
Water thoroughly and wait 24 hours — plump pearls typically rehydrate within a day. If the plant is extremely pot-bound or the soil has gone hydrophobic, soak the whole pot in water for 20 minutes to rehydrate the root zone, then drain thoroughly.
Long, thin, stretched strings
Symptom
Strings extend rapidly with widely-spaced pearls and pale colour.
Cause
Insufficient light — the plant is reaching for better conditions.
Fix
Move to a brighter spot (direct morning sun or a grow light). Trim stretched strings back and propagate the cuttings into the pot to fill in with dense new growth under the better light.
Brown or black pearls
Symptom
Individual pearls go brown/black and eventually drop.
Cause
Sunburn (if only pearls on the sun-facing side are affected), or rot (if pearls are soft when squeezed).
Fix
Sunburn — shade the plant during the hottest hours or move slightly back from the window. Rot — see mushy-string treatment above.
- Mealybugs
- Aphids
- Spider mites
- Root rot (Pythium, Phytophthora)
- Botrytis grey mould
Toxicity & safety
Sap is a skin irritant in sensitive individuals. Ingestion causes mild oral irritation and digestive upset. The genus Senecio (the old name for Curio) historically included species with hepatotoxic pyrrolizidine alkaloids, though rowleyanus is at the low end of the toxicity scale.
Curio rowleyanus — Missouri Botanical Garden Plant FinderVomiting, diarrhoea, lethargy, and drooling after ingestion. Skin contact with sap can cause contact dermatitis.
String of Pearls — ASPCA Toxic and Non-Toxic PlantsVomiting, diarrhoea, lethargy, and drooling after ingestion.
String of Pearls — ASPCA Toxic and Non-Toxic PlantsEach pearl is a leaf that has evolved into a sphere to minimise its surface-area-to-volume ratio — the geometric shape that loses the least water per unit of tissue in hot, dry environments. The translucent longitudinal line on each pearl is a 'window' that lets sunlight reach photosynthetic tissue deep inside, while the rest of the surface reflects away drying sun. The same adaptation appears independently in several unrelated African succulents (e.g. Haworthia truncata, Fenestraria).
Frequently asked · 5
Is string of pearls toxic to cats and dogs?+
Yes — ASPCA lists Curio rowleyanus (string of pearls) as toxic to cats and dogs. The sap contains compounds that cause vomiting, diarrhoea, lethargy, and drooling after ingestion; skin contact can cause mild dermatitis. Keep strings out of reach of pets that chew plants.
Why is my string of pearls dying even though I water it?+
The most common cause is overwatering, not under-watering. Curio rowleyanus is a xerophyte and stores weeks of water in its pearls — water deeply only every 2–3 weeks in summer and monthly in winter, and never while the top 2–3 cm of soil is still moist. Use a fast-draining gritty cactus mix and a pot with a drainage hole.
Why are my pearls shrivelling?+
Shrivelled pearls usually mean under-watering or a hydrophobic, root-bound soil that isn't absorbing the water you add. Water thoroughly and give the plant 24 hours; pearls usually plump back. If the pot is very root-bound, soak the whole pot in a basin of water for 20 minutes to rehydrate the root zone, then drain fully.
How much light does string of pearls need?+
Very bright indirect light, with some direct morning sun ideal. It needs substantially more light than most aroid houseplants — place it within 1 m of a south or east window, or directly in a west window (filter harsh afternoon summer sun). In Nordic winters, a full-spectrum grow light is nearly mandatory from October through March.
How do I propagate string of pearls?+
The easiest method is laying cuttings on soil: snip a 10–15 cm string, let the cut end callus for a day, then lay flat on the surface of dry cactus mix. Press lightly and mist every 3–4 days. Strings root at every node in contact with soil within 2–4 weeks and fill a pot quickly.