What next for holiday poinsettias?

Poinsettias have now taken charge as the top Christmas plant. I could say the top Christmas “flower” but that’s not strictly true. The parts of the plant that provide all the colour are not flowers at all – they’re bracts, which are like modified leaves and which surround the true flowers and do the work of enormous showy petals.

With their rise in popularity around the world, plant breeders are working flat out to develop new poinsettia varieties in new colours: there are plenty of pastel shades, now, along with bicolours and even some with their bracts speckled in white. Other aims are plants that thrive at lower temperatures, tolerate low light levels, branch naturally without pinching, and which retain their colour for longer in the home.

How to get poinsettias to re-flower next year

Many of us enjoy our poinsettias so much, especially the large and impressive plants now often available and those in unusual colours, that we’d like to keep them, and grow them into even larger plants to enjoy again next winter. Here’s how:

1. When the plant has lost its appeal, cut it back by about half

2. In May or June, move it into a larger pot

3. Keep it above 13°C/55°F - it can even go outside in summer

4. Feed regularly with a high potassium liquid feed, and keep moist during this time

5. Check often for whitefly and control if necessary

6. This is the tricky part: from early October, the plant needs fourteen hours of complete uninterrupted darkness to initiate buds for a Christmas display. This can be done with a large upturned cardboard box, an upturned dustbin or the plant can be put in a completely dark cupboard. Any chink of light will waste your effort

7. During its ten hours of daylight the plant needs good light and a temperature of at least 13°C/55°F

8. Around the end of November the bracts will start to colour and the daily covering can be abandoned

This will work – if no light seeps in. But what a palaver! Eight weeks of daily covering and uncovering, and you have to put up with a box or bin in your conservatory. What’s more, frankly, they never look as good second time around; in particular, the stems are often spindly and weak.

Here’s my advice:

1. When the plant starts to look tired in March, use your secateurs to cut the stem off at soil level

2. Dump all the top growth on the compost heap

3. Leave the pot in a corner outside for the roots to rot over the winter and then use the old compost to help improve the garden soil when planting in spring

4. Next, December – buy a new plant

That’s my view. You can check up on the official RHS approach to poinsettia care.