I've been trying to determine what was wrong with this Crassula tetragona since May. Had suggestions for drainage, potting mix, sunburn, etc., but just one person suspected pests. Pallas Athena, you have spider mites too. Did yours recover? Remember how this looks and progresses so you can protect your own plants. Mites aren't visible. I couldn't see them even with a magnifying glass. I needed the macro lens of my "real" camera, then I had to enlarge the image. It begins as yellowing of leaves for no apparent reason. Old leaves are mostly affected, but newer leaves sometimes also. Leaves drop. Some shrivel. People mistake it for over-watering, poor drainage, sunburn, etc. As it progresses, leaves look textured with tiny indentations about pin pricked size. Leaf surfaces get what looks lime a brown or black coating, stain, or discoloring. Plants continue to grow and produce more leaves and branches, but eventually only those newest leaves remain healthy. That's where my plants are now. I can save them, but it'll be a huge setback. Worse, they've been in contact with all my other plants, shared a wager bucket, etc., so I'll be treating a lot of plants. Hopefully, this mite doesn't thrive so well on other plants. Update: I washed it in alcohol and dish soap, and wiped all the areas I could reach with a Q-tip. Many more leaves came off as I did it. I don't know if thatll be enough, but I can't find any evidence of other plants also being affected, so I hope it was just this one plant the little b******s liked. I don't want to resort to nasty chemicals. This post was edited by kwie2011 on Mon, Oct 27, 14 at 16:59

Hi! Thank you Gill and Andy. I had a b&q trip and made the mix you suggested Gill. The roots looked ok to me (white and dry) and they'd grown a lot since I last re-potted it - so I think that's positive. If it would be better out of the heat during our 'heat wave' (hottest day in 9years!? Apparently) I'll pop it in one of the other rooms for a while. I did read the link you sent Andy, very interesting and informative. I admit I never even thought about air availability in the soil! Bought a good quality potting mix instead of the cactus mix. Thanks again. I'll let you know if it's improved in a week or so! *fingers crossed*

The triple whammy of heat, repotting and dividing may have been too much. I'm not really a crassula guy-I only have a dozen different ones- but. . . . .I keep mine in half shade in the summer, water more, although still allowing to dry out between waterings. Dormancy is a vexed question, whether it really is a factor in the artificial environments we create for our plants. I bought the same plant a month or so ago. I never take the old soil off-just pop it into the new pot and better mix. Plant is growing nicely with good color, so maybe you just stressed yours too much.

The immediate cause is a stronger than usual expression of the purple pigment, anthocyanin. The underlying potential cause that jumps out would be a cool soil. Did you turned the heat way down while you were away? If so, that could be the cause. Reason: It's difficult for most plants to assimilate (P)hosphorous as phosphate when soil temps are in the 50s (Farenheit) or lower. P is required to make ATP and ATP is needed to turn sugars to starch, and is essential to loading of sugar into phloem tissue for transport throughout the plant. No P = no ATP = no move sugars/starches = anthocyanin (purple pigment) builds up = plant turns purple. Typically, areas of a plant that are genetically predisposed to turning purple would present first, but higher concentrations of the purple pigment wouldn't necessarily be limited to the predisposed parts. That you have entire leaves turning purple is a good indication that something is limiting P uptake. High levels of Ca in the soil solution can also limit P uptake, so as the soil dries down, Ca concentrations in the soil solution increase. Either factor can work individually or in concert to cause the symptoms. Al