Q Should I cut back a two-year-old poinsettia?
Sally Anne Crookes, by email
A BOB SAYS Poinsettias are indeed difficult to keep going and looking good, though they can make fabulous garden exhibits if planted outdoors in the ground once the soil is warm.
However, then you cannot unearth and re-use the plant as the brittle roots will break away. You have done well to keep it looking good for so long and have avoided poinsettias’ worst pitfall, which is drying out causing leaves to drop.
Obviously, you’re giving this enough light in summer though, as you know it will need 14 hours of complete dark a day for a month to come into flower.
You have a choice now: keep the main plant, cutting it back hard in late spring/early summer, repotting that in fresh compost and treating the pieces removed as cuttings, or plan to dump the original (recommended) and take strongly growing shoots as cuttings in late summer, when they will root more easily (especially if given bottom heat as they need 20°C to succeed).