How to Grow Senecio rowleyanus, or String of Pearls succulent

String of Pearls, or Senecio rowleyanus, are one of the absolute most popular succulents out there. They’re extremely distinct, and even people who aren’t super familiar with succulents, houseplants, or greenand growing things in general would probably recognize them. 

Unfortunately for the plants and the people who Just Have To Have Them, they aren’t actually the bomb-proof houseplant that Pinterest or random Instagram accounts would have you believe. If you’ve already tried your hand at growing a few of these, and failed, you’re far, far from alone. Most people (myself included) killed their first String of Pearls, and maybe even a few more after that. Luckily, once you do get the care dialed in, you’ll discover that they are in fact quite easy to grow. It’s understanding what they actually need that tends to trip people up. 

Why do people struggle with String of Pearls so much? Probably lighting. 

The first mistake that seems to happen for folks trying to grow String of Pearls is usually related to light. They’re not house plants, they are succulents, and need light like a succulent.

Trying to grow them inside? They need to be in lighting conditions as bright, if not brighter than, what you’d grow a large monstera or fiddle leaf fig tree with. If you’ve struggled to grow succulents indoors and thought String of Pearls would be easier, you were wrong. Indoors, they need extremely bright light, preferably near a south facing window. Use a light meter or a light meter app to find a spot that gets pretty consistently about 400 – 500 foot candles for most of the day. Alternatively, if your window gets 1000+ for an hour or two in the morning, and then it dips down to the low 100 – 200 range, that might work. 

Don’t have a spot that’s that bright? Your string of pearls is unlikely to thrive, plain and simple. 

You might see them in photos or magazines in spots that are very clearly not by a window, or in an area that gets a lot of light, and a very important thing to remember about these images is that they are staged for the photos. Just like the furniture and artfully placed humans lounging on said furniture, the plants don’t exist there all the time. 

Outdoors, you’ll have an easier time with these, mostly. If you’re in an area warm enough for them year round, place them somewhere that gets an hour or two of morning light (at least) and shade the rest of the day. With patience, you can get them acclimated to significantly more sun, although they won’t be as green and plump. I have a bundle that I forgot about sitting out in an area where I have my aloes for sun stress, and while the pearls aren’t exactly happy about their circumstances, they survived. 

They tend to look their best with at least an hour or so of morning sun, up to 3 or 4 hours, and then shade from about noon onward. They’ll grow nice, even strings with nice round leaf bodies. 

A pot of very sad, half-dehydrated, and tanned pearls that I had forgotten next to my aloes for several months. Not dead, but definitely sad.

Other General Guidance and Myths

Lies people tell about Senecio rowleyanus include, but are not limited to, “they have weak, shallow root systems” and “they sunburn easily” and “they need to be kept warm all the time”.

Weak, shallow root systems: 

This one is probably because people don’t unpot/handle roots as often as folks who ship these guys bare roots, so you don’t see the rather extensive, vigorous, and determined root systems these guys get when they’re happy. Just because the main roots of the plant can go into relatively small pots, doesn’t mean they are lacking in solid roots. When potted correctly, with a porous soil that dries quickly and given appropriate light, these will develop a solid set of roots that wedge themselves into anything. I’ve had to pry the roots out of neighboring pots, the cracks in their own pots, and one time even the siding of the house. They are determined.

That doesn’t mean stick your 4″ pot of pearls in a 6″ azalea pot; it just means that your typical succulent pot that tends to be shallower will work fine. It also means that if you want to try and stick them in a tall narrow pot for DrAmAtIC eFfEcT, you can, but just be aware you’ll need a super porous blend to allow for the roots to crawl down and absorb moisture appropriately.

Sunburn easily: 

This is usually because when you bring these straight home from a nursery, you’re taking them from the sheltered, idealistic growing conditions they were propagated in to your harsh, unyeilding home with its blazing sun. I can’t have these out unprotected without slowly acclimating them to more intense levels of sun, and even then, these definitely prefer more shade than most succulents.

That being said, I’ve also seen these growing as a goddamn carpet underneath cactus benches at nurseries, just with a bit of a tan.

Don’t mistake the brown blushing they develop in intense sun for actual sunburn. I talk about actual sunburn here. When your String of Pearls get sunburnt, they will turn a crispy yellow-white, sometimes a mushy brown, but never the dusted brown/red that a sun-hardened senecio will turn. If your string of pearls are just darker than what you see online, it’s literally just a tan. You might want to move them to somewhere a little shadier during the afternoon if you want them to be nice and green, but the brownish coloration is just the plant protecting itself from the sun. The carpet of string of pearls I saw at a cactus nursery was pretty much entirely brown rather than green due to the amount of sunshine they were exposed to.

Keep warm (room temp) all the time: 

The string of pearls I leave exposed to 30F weather on the regular would like to have words with the people who say this. I will say that unless they are quite bone dry when nighttime temps hit the mid 30s, they will definitely rot right out.

If your weather is cold but you don’t get hard frosts, these are just fine with night time drops to the low 30s if you let their soil dry out. The dry soil is key: in their natural environment, these plants only experience temperatures that low during their dry season. When it’s cold, they’re somewhat dormant, and that’s why you need to keep them dry – they won’t be absorbing or using any water, and the longer their roots sit in the wet, the more likely they are to rot.

Basic String of Pearls Care

Plant your string of pearls in a pot only a little bigger than the pot size you bought it as. If you got it as a 2.5″ pot, moving up to a 4″ works, but you may need to propagate additional strands to fill the pot. The plants won’t fill out at their base – they just get longer, not fuller, so if you want a big full pot, you’ll have to fill it with a couple smaller plants or get a bigger plant to begin with.

Use a succulent mix as the soil. Most standard “big bag” mixes you’ll want to mix with about 1/4 to 1/3 additional pumice or perlite for drainage, but if you’re using a smaller bagged blend such as Bonsai Jack or whatever is on Amazon these days, those are probably already mixed with more porous material. I don’t personally use those blends, and tend to mix my own, so you’ll need to use your judgement with that. If the soil has lots of pumice and big chunks in it already, you probably don’t need to add much to keep it aerated.

Make sure you pot the pearls so that they are pretty much flush with the top of the pot – you don’t want them to be sunk in significantly. Something about being sunk in seems to lend itself to rotting out the stems or pearl leaf bodies, so you’ll want them to be pretty much flat with the upper edge of your pot.

Water sparingly. When you first pot up your pearls, give them a good soaking, and then after that lift up and check under the bottom of the pot to see if it’s dry all the way through before watering again. If you’re finding that the bottom stays wet looking even as the pearls start to wrinkle, use a small watering can or cup to only add a small bit of water up top. Give them a light splash, just enough to see the soil get damp, then check the pearls the next day to see if they’ve plumped up. If not, water again.

Alternatively, you can go the nursery route, which is to water from the top until the water is flowing straight out the bottom, which works well if you are letting your pearls get dry enough to start to wrinkle or prune. If you flush the soil thoroughly this way, you can get by with the bottom never fully being absorbed by the plant; by flushing it, you’re removing the stagnant water before bacteria and other problems creep up. A key element of this method is to let the water truly flow out the bottom. It needs to be a steady stream before you stop watering up top, and the weather needs to be favorable enough for the top of the plant to dry out by the end of the day.

When in doubt, water less. String of Pearls can get downright raisin shaped before they actually die, and being left to get a bit pruny is far better for them than being overwatered.

You probably don’t need to fertilize these much, if at all, but if it’s been over a year since you potted your pearls, a couple times a year in spring and/or summer you can fertilize them with a dilute feeding of succulent fertilizer, fish emulsion, and/or worm casting tea. They don’t need much, but a little bit of a boost when the soil starts to get stale can be helpful to encourage growth and blooming.

Keep in an area with plenty of bright, indirect light. For long term growth, I’ve had these do quite well when kept near my Monstera deliciosa plants, in an area with direct morning sun for a couple hours early on, and then shade for the rest of the day. They are in a spot they share with my variegated string of hearts, and in general, that bright but sheltered area works quite well.

Sadly, I don’t have any photos of long, trailing plants to show off because a) I tend to list the 4″ pots once they start to look cool and b) because we have a problem with rats and the little shits like eating my string of pearls.

While wikipedia and the internet like to mention that these are mildly toxic, I’ll note that I’ve never had skin irritation from the sap, and considering how much the local rats like to munch on them, I don’t think the rats find them all that toxic either. Maybe we have super rats? Either way, science-y folks at University of California, Davis, have included these in a list of poisonous garden plants, so try to restrain from eating them.