Curio Rowleyanus ‘String of Pearls’ Care Guide (2022)

string of pearls

String of Pearls is a fascinating houseplant with a really unique appearance.

While it was previously known as Senecio rowleyanus, its accepted name is now Curio rowleyanus.

Its long, dangling vines studded with small, spherical leaves will add a whimsical touch to any space.

Quick-growing and low-maintenance, this succulent hanging plant is perfect even for beginners.

Scientific NameCurio rowleyanus
Common NameString of Pearls, Rosary Plant, Irish Beads
LightFull to indirect sunlight
WateringWater when soil is dry
Temperature70 to 80 ºF (21 to 27ºC)
Hardiness Zone9b to 12
Humidity40%
Soil TypeQuick-draining, sandy
Soil pH6.6 to 7.5 (neutral)
FertilizingA balanced feed at the beginning of the growing season
RepottingEvery 5 years
PruningBeginning of the growing season
PropagationRoot in water or soil
ToxicityToxic to humans and pets
Mature Size3 to 6-foot vines as a houseplant
Bloom TimeSpring

What’s Unique About String of Pearls?

The String of Pearls plant is native to the western Cape of South Africa in the Karoo shrubland, where it grows into thick mats across the rocks in the desert.

String of Pearls plants are prized for their small, spherical leaves which look like peas. They grow in profusion along the long, trailing vines.

Growing String of Pearls is not difficult if you can learn to leave it alone; it thrives on infrequent watering and fertilizing, and rarely even needs repotting.

Because of its trailing habit and unique foliage, a String of Pearls plant is a lovely accent in a contemporary setting. 

String of Pearls Care

In the deserts of south-west Africa where String of Pearls originates, these succulent plants evolved in a hot, dry environment without much shade.

In your home, String of Pearls plant care should try to mimic these native growing conditions as much as possible.

Curio rowleyanus care comes down to sunlight, heat, and low moisture levels.

Light 

The String of Pearls light requirements are not the same as for many houseplants.

Curio rowleyanus light needs are for full sun to bright, indirect light, or between 20,000 to 50,000 lux.

You should find a spot close to an east, south, or west-facing window for the best growth of your String of Pearls.

If all you have is a northern exposure, you will need a grow light for your String of Pearls to give it the intensity of light it needs to thrive.

Be aware that too much direct sun may actually damage your String of Pearls; in a south window you may need to provide some screening in the mid-afternoon.

Watering 

String of Pearls is a desert native, so it has evolved to survive on little water. 

String of Pearls watering should only be done when the soil is almost dry. Check this by the weight of the pot, which will be very light when there’s no moisture left in the soil. 

You can also tell when the leaves start to look a little shriveled that it’s time to water Curio rowleyanus. 

It’s best to water your String of Pearls from below, so that the surface of the soil stays as dry as possible. You don’t want the pearls lying on the soil to rot.

String of Pearls watering needs will be lower in winter when light levels are lower and it’s not actively growing.

Temperature 

It is hot in summer and warm in winter in the Karoo desert, so the String of Pearls temperature range is roughly 70 to 80 ºF (21 to 27ºC). 

If you can adjust the temperature for Curio rowleyanus so that it’s kept between 55 to 65 ºF (12 to 18ºC) in winter, it will grow even better.

String of Pearls has little temperature tolerance below 50ºF (10ºC), so keep it out of drafts.

While temperatures in its native habitat sometimes dip down towards freezing, String of Pearls is not considered to have any frost hardiness. 

If you take it outside for the summer, bring it in long before freezing temperatures are expected.

Humidity 

The String of Pearls humidity requirements could not be easier to meet in any typical home environment.

In fact, too high a humidity level is detrimental to this desert native. This is one houseplant that should not be kept in a bathroom.

The ideal humidity for Curio rowleyanus is 40% or lower, so any standard heated home should be perfect for your String of Pearls without using a pebble tray or humidifier.

Do not, under any circumstances, mist your String of Pearls foliage. Not only does it not need the extra moisture, but in fact this can cause disease to develop.

Soil 

Your String of Pearls soil has to be very loose and porous. This desert native is used to growing in very sandy, gravelly ground.

The best pH level for Curio rowleyanus is 6.6 to 7.5, or neutral. 

Never use plain potting soil for your String of Pearls, as it will stay far too moist.

You can use a commercial cactus or succulent soil for Curio rowleyanus, as it is perfectly formulated for these plants.

However, you can also make your own soil mix with equal parts of potting soil and coarse sand. 

Adding pumice and vermiculite will create an even looser soil for your String of Pearls.

Fertilizer 

While you should use some fertilizer for Curio rowleyanus, it’s best not to overdo it, as too much will damage the plant.

The best fertilizer ratio for your String of Pearls is a balanced 10-10-10.

The safest String of Pearls fertilizer is also the easiest. Simply spread a layer of compost or worm castings over the soil surface. 

Do this at the beginning of the growing season in spring, and then again in midsummer. 

However, you can also use a liquid fertilizer once a month in spring and summer, diluted to half strength. 

Apply it shortly after you’ve watered your String of Pearls.

Potting & Repotting 

String of Pearls repotting is rarely necessary, as its shallow root system rarely outgrows its pot.

Some growers recommend repotting Curio rowleyanus only every 5 years, while others repot annually. 

However, you should not keep to a schedule, but rather repot when you see roots growing out of the drainage holes. That is a clear sign that your String of Pearls is becoming rootbound.

Only go up one pot size, as too big a pot can lead to watering issues. It’s very important that the new pot has drainage holes. 

Unglazed clay is a good choice to help regulate soil moisture.

Always use fresh potting soil, using a mix formulated for cacti and succulents.

Pruning 

While you won’t want to do too much String of Pearls pruning, sometimes it’s necessary to keep the plant looking neat and tidy.

The best time to undertake a major pruning is in early spring, at the beginning of its growing season.

Any time the vines are getting too long, feel free to cut them to your preferred length. Also trim off dead leaves and flowers, as well as any stems that don’t have a lot of leaves.

When cutting Curio rowleyanus, use sharp, sterilized scissors to avoid spreading disease.

Cut the stem just below a leaf to encourage fresh new growth. If you are trimming off dead or damaged stems, cut well above the affected parts. 

Propagation 

String of Pearls propagation is very simple using stem or leaf cuttings.

The easiest way to propagate Curio rowleyanus is to simply take a length of stem, and lay it down on the surface of moist soil. You can wind around a long piece to fit in the pot. Just make sure that the stem is in contact with the soil.

You can also take an individual leaf and let the cut end callus over for a few days before pressing the cut end into damp soil.

Finally, you can strip the lower leaves off a short stem section and plant it cut side down after letting it callus for a day or two.

All of these methods should result in new roots growing in a month or so.

Common Problems of String of Pearls

There really aren’t a lot of potential String of Pearls problems. 

Most common problems with Curio rowleyanus can be prevented or resolved with proper growing conditions.

When the leaves of your String of Pearls look fresh and perky, you can be sure that you’re doing things right. If not, you should be able to diagnose and solve the problem easily.

Pests 

The two most likely String of Pearls pests are mealybugs and aphids.

The best way to deal with bugs on your Curio rowleyanus is by preventing them from turning up in the first place.

A monthly spritz of an insecticidal solution such as neem oil or insecticidal soap is your best bet to keep these insects at bay.

However, if they slip past your defenses, you should be able to easily get rid of them.

Mealybugs will resemble little tufts of cotton on the leaves and stems. Spray them with rubbing alcohol to kill them.

Aphids are small, green flying insects. Give your String of Pearls a gentle spraying in the sink or shower to clean them off.

Diseases 

There are very few String of Pearls diseases to worry about. 

In fact, the only disease you’re likely to see affecting your Curio rowleyanus is the classic houseplant nemesis, root rot.

This is caused by leaving the roots of String of Pearls sitting in wet soil, cutting off their ability to breathe and fostering fungal diseases.

If the leaves start turning yellow, and stems are getting mushy, pull the root ball out and see if there are black sections.

Cut out all the affected roots, stems, and leaves, and replant your String of Pearls in porous, loose soil in a disinfected pot.

Growing Problems 

Most growing problems with String of Pearls aren’t caused by diseases or pests, but are rather the result of poor growing conditions.

When your sick plant is given a more ideal situation, it should come roaring back to health.

Shriveled leaves are a clear indication that your String of Pearls needs water. When even its succulent tissues have run out of moisture, it’s time to give it a good drink.

Browning leaves are usually caused by too much direct sun. Move it away from the window or hang a light curtain to shade it slightly.

If your String of Pearls’ crown is rotting, it’s planted too deep in the pot. You may not be able to rescue it, so take some healthy stem cuttings and propagate them to replace the rotted plant.

Toxicity of String of Pearls

Curio rowleyanus is toxic to humans and most common household pets.

Its toxicity is caused by the pyrrolizidine alkaloid in the sap, which can be found in all parts of the plant.

It can cause short-term effects like vomiting and diarrhea, as well as long-term liver damage if it is consumed over a period of time.

For Humans 

String of Pearls is toxic to humans.

Exposure to the sap can cause a rash, so wear gloves when handling the plant, and wash off any sap that gets on your skin.

The bigger concern in your household is for any children who may be around, as the small, round leaves may seem like candies.

The leaves are somewhat prone to fall off the vines, so a child could easily get their hands on some and eat them.

If your child eats a few leaves one time, they may have vomiting and diarrhea, but if they continue to eat them, over time they could suffer liver damage.

Take your child to the emergency room if they have ingested any String of Pearls leaves.

For Pets 

String of Pearls is not toxic to all pets, but certainly to cats and dogs, as well as birds and turtles. Rabbits are not affected by the toxins.

Dangling vines will be a definite attraction to cats, and dogs may gobble up anything that they find on the floor.

If your cat or dog has diarrhea or vomiting, or excessive drooling, take it to the veterinarian at once, as treatments to prevent liver damage should be started quickly.

If you want to grow String of Pearls in a household with pets and children, keep the trailing vines trimmed short to be out of reach.

As well, consider hanging it where the floor underneath will be inaccessible.

String of Pearls Appearance

You can describe the String of Pearls appearance as cute or contemporary, depending on your tastes.

The trailing stems hung with small, round green balls are both quirky and sleek.

As well, the rapid growth rate means they will soon be a dominant part of your indoor or outdoor garden.

Foliage 

The foliage of String of Pearls is certainly different from most other houseplants.

Each leaf is a small sphere, about a third of an inch across. They are a bright medium green.

They are not completely round, as there is a small tip at the end.

String of Pearls evolved in a desert climate, so the spherical shape conserves water, as there is less surface area to transpire moisture.

However, that also means less surface area for photosynthesis, a problem which is solved by the darker green stripe down one side of each leaf.

This stripe is essentially a window which lets light into the interior of the leaf.

Flowering 

While you are more likely to get your String of Pearls flowering when grown outdoors, a few simple tricks can get it blooming indoors.

String of Pearls needs cool winter temperatures of about 60ºF (15ºC) with very little watering to trigger blooming the following spring and summer.

When you bring your String of Pearls back into warm surroundings in early spring, put it in as bright a location as possible, and fertilize twice a month.

The Curio rowleyanus flower is quite pretty, being a round ball of tiny white blossoms with red stamens and yellow anthers sticking out all around.

Size and Growth 

The size of String of Pearls is really a matter of length; while the crown does not get very tall, the vining stems can trail as much as 6 feet if not trimmed.

It has a rapid growth rate, reaching its full size in 2 years.

String of Pearls is usually grown as a trailing plant in a hanging basket.

However, if you are growing it outside you could let it spread as a ground cover much as it does in its native desert.

String of Pearls has a fairly short lifespan, with many plants declining after 5 years. You can easily propagate new plants to replace the old ones.

String of Pearls Fragrance

If you are lucky enough to get your String of Pearls to bloom, you will get to enjoy the very pleasant String of Pearls fragrance.

For about a month or two while String of Pearls is flowering in spring and early summer, the sweet, spicy scent of cinnamon will waft its way through your home.

It’s a lovely scent, but at the same time not cloying or overwhelming, so it’s perfect for a small space like a studio apartment.

However, if you do not appreciate the scent, you can cut the flowers off as they emerge and instead enjoy the evergreen foliage.

Suggested Uses for String of Pearls

String of Pearls is a fascinating plant that can be used in a variety of settings to complement a contemporary or cottage-core decor.

Indoors, you can hang your String of Pearls planter in front of a south window to screen an unattractive view. 

Because they’re so easy to propagate, you can work with multiple plants to create a wall of trailing greenery for a living tapestry.

Outdoors in zones 9 to 12, you can let String of Pearls spread across rocks or gravel to form a solid mat of ground cover or hang a whole row as a backdrop on a sunny porch.

FAQ

What is String of Pearls? 

String of Pearls is a succulent evergreen plant native to the deserts of south-west Africa. It is commonly grown as a houseplant for its unique foliage.

How to identify String of Pearls? 

String of Pearls has small, spherical leaves growing on long trailing stems from a low central crown. The leaves are green with a stripe down one side.

How to care for String of Pearls? 

String of Pearls can be grown as a hanging plant, potted in loose, porous soil and kept in a bright location in a warm spot with low humidity.

How to grow String of Pearls indoors? 

String of Pearls can be grown indoors in a warm, sunny spot, watered only when the soil is almost dry and fertilized once or twice a year.

How to grow String of Pearls outdoors? 

String of Pearls can be grown outdoors year-round in zones 9b to 12 as a hanging plant or ground cover. In temperate zones, plants can be moved outside in summer.

How fast does String of Pearls grow? 

String of Pearls has a fast growth rate, taking 2 years to reach its full size. Plants are fairly short-lived and will probably need to be replaced every 5 years or so.

How tall does String of Pearls grow? 

String of Pearls is a trailing plant, so does not grow very tall, but the stems can reach up to 6 feet in length with a spread of 1 to 2 feet.

How to make String of Pearls grow faster? 

String of Pearls is already a fast grower, but it will do its best in warm temperatures and a very sunny location. Do not fertilize to encourage growth.

How to stake String of Pearls? 

String of Pearls is a trailing plant so it should not be staked. It can also be grown as a ground cover outdoors in tropical or subtropical climates.

How to pot String of Pearls? 

String of Pearls must be potted in a very loose, porous soil mix to ensure good drainage, in an unglazed clay pot with drainage holes.

How to revive String of Pearls? 

If your String of Pearls has dried out completely, put the pot in a pail of water and let it slowly absorb water from the bottom. Try to not saturate the soil surface.

Why is my String of Pearls dying? 

Your String of Pearls may have root rot from growing in too wet soil. Cut off all affected parts and repot in loose, porous soil and cut back on watering.

Why is my String of Pearls drooping? 

Your String of Pearls may be drooping because it is too dry or too wet. Check the soil’s moisture levels and either water it well or cut back on watering.

How cold can String of Pearls tolerate? 

String of Pearls prefers to grow in normal room temperatures, and will not thrive below 50ºF (10ºC), so keep it out of drafts. It has no frost hardiness.

How to get rid of pests on String of Pearls? 

String of Pearls pests can be prevented by spraying the entire plant once a month or so with an insecticidal soap or neem oil solution.

Is String of Pearls toxic to cats? 

Yes, String of Pearls is toxic to cats. If your cat has vomiting, diarrhea, or excessive drooling, take it to the veterinarian as soon as possible.

Is String of Pearls toxic to dogs? 

Yes, String of Pearls is toxic to dogs. If your dog is drooling more than usual, or has vomiting or diarrhea, you need to take it to the vet.

Is String of Pearls toxic to children? 

Yes, String of Pearls is toxic to children. If your child is vomiting or has diarrhea, take them to the emergency room as soon as possible. 

Is String of Pearls toxic to humans? 

Yes, String of Pearls is toxic to humans. Wear gloves when handling the foliage, and rinse off any sap that gets on your skin, as you can get a rash.

Does String of Pearls have a scent? 

Yes, String of Pearls flowers have a pleasant spicy scent reminiscent of cinnamon. They bloom in spring for a couple of months. The foliage, however, has no fragrance.

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