I have an Euphorbia that I bought over 30 years ago. Three times it has drooped. Each time I took some cuttings, and planted them in new pots. The first two times, I replanted the original plant in a new pot. The third time, I just tied it up with support poles and after a few weeks it was able to support itself once again. It is now drooping again. I could follow what I did before, but if would really like to know why this happens. It certainly looks healthy, but some of the stems are simply not stiff enough to stand up. Does anyone know what causes this. I am pretty sure it is not being over watered. See the photo I have attached. Only some of the stems are drooping...
Looks like it is slightly etioliated, i.e. the stems have grown thin and weak because the light and temperature have been less than ideal. This is very common in succulent plants kept indoors, where the light is reduced by walls, curtains and window blinds but the relatively high temperature makes the plants grow faster than they should (especially in winter). When the plant grows big enough, the stems cannot support the weight anymore.
That makes sense, but leaves me with even more questions. 1) what triggers it to droop? It is fine one day and the next it droops. If I prop it up with supports, then in a few weeks it suddenly can support itself again. These drooping spells are years apart. 2) how can a plant's growth be slowed during the winter months when it is inside?
Sounds odd (but I don't grow Euphorbia). I wonder if it forms some wood during these weeks, or if it just takes upp more water and becomes more turgid? Cannot make a better guess without observing the plant directly. Stop watering. For my cacti and in my climate, September–October is a good time to stop. Lower temperature helps a lot too, but is not always possible indoors, especially with large plants. I put some of my smaller cacti in the fridge. Start watering again in spring (for me this usually means May).
