Poinsetta

How do I keep Poinsetta leaves red?

You can't keep the "leaves" red as they are the flowers and, as with all other plants, they will die off.

You will need to do the following approximately 8 weeks from when you want the leaves to turn red.

During the day, the plants need bright light, along with the other routine care. However, starting in the evening, the plants must get complete darkness for 14 hours each day. Even a chink of light can disrupt this process!

The bracts will start to turn color in about four weeks, and continue if you carefully keep up the process. Make sure that the environment is humid during this time, but be careful not to spray the foliage directly, as you may invite leaf spot and you don't want that on this plant (or any!) In about eight weeks, the bracts should all be red, if you’ve followed the above guidelines. They’ll stay this way for several weeks, at least until after Christmas.

Eventually the leaves will start to drop off. Once this occurs, cut the stems back to four to six inches. Keep the soil fairly dry, and the plant warm until new growth occurs. At this stage you can either plant it in the garden or re pot it but make sure you add a light amount of fertiliser in the spring and summer.
Come next October, start the whole process over again!