From correspondence received, similar questions about cultivation of succulent plants keep recurring. Often insufficient information is provided to diagnose the problem, but the largest single cause of sick plants, typified by the second question, is probably over-watering. Follow links for more information.
Q. What is this plant ?   (This is probably the most frequent query.)
A. As aids to identification, see:
for some commonly-grown plants that have turned up in queries.
for a list of all the illustrations.
currently ca. 10Mb so will take time to load.
the family, species or common name of your plant. It is surprising how many images of obscure plants can be found on the internet. However, beware of inappropriately named images. Look for a concensus.
Q. My succulent plant / cactus has gone soft and grey, or yellow or is dying. What do I do ?
A. This may well be a symptom of over-watering. See: Cultural Problems.
If the plant has gone soft, yellow, grey or mouldy it is probably too late to save it. However, if part of the plant is still firm and healthy, it may be possible to save it as a cutting or graft.
See Propagation methods.
Q. My cactus / succulent has little balls of white fluffy stuff on it, particularly around the spine clusters or growing points. What do I do ?
A. The white material is produced by female Mealy Bugs nesting up to produce young.
See Mealy Bugs for information and control measures.
Q. Why is my plant is going brown on top, especially around the growing point ?
A. This may indicate damage from pests such as Red Spider Mite or a Cultivation Problem such as scorching.
See Red Spider Mite for information and control measures.
Also review Cultural Problems.
Q. How do I re-pot my very spiny cactus ?
A. See cultivation hints: Repotting a Prickly Customer
Q. I have a very tall cactus that may fall over. What do I do ?
A. A top-heavy plant can be stabilised by providing a larger or heavier pot or by putting its pot into a larger one as a support and packing the gap with grit or pebbles. It is also possible to cast concrete blocks with a pot-sized hole in them as supports.
Q. My very tall cactus fell over and the stem broke in two. What do I do ?
A. The bottom half may well offset to produce side-shoots in a few months, or at the start of the next growing season. You can grow this part on as normal, but if you want to trim the broken surface, use a very sharp knife that has been sterilised by dipping in methylated spirits/industrial alcohol. The top half can be allowed to dry and the raw end callus over for a couple of weeks before potting up in a gritty potting mixture. You may wish to treat the broken end with some hormone rooting powder, particularly as this usually also contains a fungicide. Water very sparingly until new growth indicates root formation has started.