Sadly I did not take any pictures before I radically gave intensive care to the plant... by that I mean I took it through to the kitchen to examine it, and realised that all the "strings" were sooo heavy they were pulling down on the damaged and weak roots and pulling them out of the earth. I think I'd been watering every couple of weeks, but possibly giving it too much, and maybe it had been sitting in an inch of water at the bottom of the pot.. i presume it didn't like that.

Anyway, I decided to pull the worst roots out, and cut off the withered dead top parts of the strings, down to the healthy part, made sure at least a couple of nodes were available and buried each string with its bare nodes back into the soil again in the same pot. I ended up doing this with every single string, since all of their roots were very unhealthy looking (but the rest of the strings look fine... ).. so I did this to about 100 strings, so that when I had finished the plant looked a lot more thinned out and less luscious and shorter, but not so heavy.. now I guess I just have to hope all those nodes I buried under the earth take root?? I really have no idea what I'm doing so I hope I haven't ruined it...

I would have not potted them into same pot/soil (..."and buried each string with its bare nodes back into the soil again in the same pot"...) if there was an 1' or so of water there (..."maybe it had been sitting in an inch of water at the bottom of the pot"...). I would use better draining mix and if reusing the container - washed it before using. There could be some unwelcomed guests in the soil that was so saturated, and even if not - soggy soil is not good for most plants.

Why was water sitting there? - is there a drainage hole? Fast draining potting mix and container with drainage hole are best for succulents, especially if new to these plants.

The strings should grow roots, they usually do even if layed across the surface just touching the potting mix - I usually put small pebble on top to keep it in place, or use a part of paper clip ("u" shape) to keep them in.

Plant also should get lots of good light.

Well, what happened was it was all in a hanging basket which should have had some stones in it to raise the pot up so that it wouldn't sit in any drained water. But the stones made the basket so heavy that it actually pulled the bracket off the wall, so I had to get them all out and just found a small plastic tub which I placed at the bottom of the basket for the pot to sit on. But it slipped off this, and I hadn't realised. So I was watering not realising the water was draining through quite quickly and possibly making the soil soggy. Although , it didn't feel at all soggy at the top. Not dry, just not that moist either.

The soil was the same that I'd originally bought the plant with, from New Covent Garden market in London - ie specialists...

Good tip about a paperclip or pebble...

Possibly it wasn't getting enough bright light over summer, though it was in the only / best possible place it could be, south facing, but not direct sunlight. Also, in London, we are about to hit a wintry and dark few months... maybe there is one other light place I could move it to. (same position but upstairs room) Now that I come to think of it, I was away for a week with someone looking after the house, about a month ago, and I have a feeling she didn't open the shutters at all in the room where all the plants are! (which she was supposed to be looking after!)

Now that I'm waiting for the roots to root should I water a bit, or just leave it? The soil feels fairly damp.

No roots - no water...this is good mantra to remember :) No point to water plant that can't take water in, moisture could just attack the rootless stems. Soil should not be damp for long time after watering. Obviously, I do not know your garden centers, but have not find one yet here that would supply 'potting mix' I prefer for succulents - I make my own, mixing grit, perlite and turface.

My plant is indoors now (much colder here than UK) and I use supplemental lights. It still gets little etiolated, but considerably less than it would without lights. I have plant for about 3 yrs now, and it started to grow much more this year, after being outdoors whole summer. Strings are over 3'long now and plant bloomed - over 40 blooms on it.

sounds lovely. DO you think the weight of the strings has anything to do with pulling the roots out and making them weaker? Good tip re no roots no water... how will I know if the roots are starting to grow? And what kind of lights do you mean?

As for the potting compost, I had just assumed that the suppliers who grow the plants and would sell them in something suitable. New Covent garden market is a wholesaler to garden centres, you can only buy from there at 5am, and they were the only place in London to get these senecio's.

sorry to ask so many questions. Thanks for all your advice.

IMO, the weight of strings should not pull them out as long as the root system is healthy. But if damaged by over- or under-watering, or possibly some disease, the roots will be weak and not able to support the plant as they should.

Succulents store lots of water in their stems and/or leaves, they are programmed to do so. The new growth signals that the roots has grown. Some ppl would advise to mist or spray the soil after a while, or just watering sparingly and not often (maybe after couple of weeks or so), trying to avoid wetting it too much and also avoiding the plants stems (as much as possible). If the leaves ('pearls') start shrivelling, that would be time to do it.

Growers of plants use mix that usually contains lots of peat. It is light (great for shipping), inexpensive, and under conditions they can supply (the growers) performs well especially for young plants, grown from seeds or cuttings. But to replicate those conditions at home is usually difficult. Peat retains too much water, if left to dry up - it becomes hydrophobic. So unless the balance of correct amount of water+temperatures+light are right on, there are many problems. Growers also keep the plants for a short period of time - they are shipped to be sold, and problems may not show that fast.

Many of us in colder climate use supplemental lights to give plants some more light. It could be just a simple light fixture hanging over a plant. It is best to use either CFL or LED lightbulbs, since they do not emit much heat and are much more economical to use. More elaborate 'grow lighting system' would be needed if there are many plants, and very low natural lighting.