Caring for your Poinsettias

                                      by Helen Gordon, Kitchener Master Gardener

The Poinsettia (Euphorbia pulcherrima) is a shrub in the Euphorbia family native to Mexico and Central America. So we know that it wants a warm home. In fact it grows best at temperatures of 20C daytime and 16-17C nighttime.  Exposure to cold, even for a brief period, causes it to droop and lose its leaves. So choose and transport your Christmas plant keeping  it cosy.

          The brightly coloured parts of the poinsettia are not the plant’s flower. They are actually modified leaves (bracts).  The flowers are the yellow-green knobs at their centre.

          Poinsettias exhibit photoperiodism flowering in  response to day length. To begin flowering they need 12 to 14 hours of uninterrupted darkness for 7 to 10 weeks. They bloom when nights are long and days are short.  The true flowers fade quickly but the coloured bracts last for four months. This makes them ideal for indoor colour in winter.

- Place your plant where it will get as much indirect sunlight as possible. Choose a place without drafts, hot or cold.

- Water it sparingly allowing the soil surface to dry out slightly between watering.

- There is no need to add fertilizer until April when 20-20-20 will help new growth along.

           It is fun to try to keep your plant from year to year. I had one re-bloom for five years until it got nipped by a late Spring frost in the garden. The secret is to prune it and repot it in late April. Cut it back by a third and mist it well. (The cuttings can be rooted as well.) Fertilize it once new growth appears. Set it out in semi-shade when all risk of frost is past and the temperatures in the 20C to 24C range.

          Water it as needed to prevent the plant wilting. Add a soluble fertilizer (20-20-20) every two weeks. Shape it with a second gentle pruning in July or early August. Never prune after September 1^st.  Bring the pot indoors in early September.

          From mid-September to mid-November allow it bright light for ten hours followed by 14 hours of total darkness daily  for eight to ten weeks. This can be done by covering the plant with a black garbage bag each night and removing it each day. Or you can place the plant under a box or in a cupboard at night and put it under a light each morning. Remember that even the light from a streetlight can ruin the dark cycle.

 

          Fertilize it with 15-15-30 bi-weekly from early November to foster bloom formation. Then enjoy your Christmas blossoms.