Red Glitter poinsettia 

Poinsettias ​(Euphorbia pulcherrima)

A Red Glitter poinsettia.

Poinsettias are originally from Mexico where they grow as shrubs or small trees that grow to a height of 12 ft.  Their bright red star shaped flowers blossom just in time for Christmas. Modern day cultivars have come a long way from the single red that used to be the norm. Now there are many more colours, colour combinations and petal count. There’s shades of pinks, reds, whites, marbled, spotted, streaked, speckled, fancy-petalled and multi-petalled.

'Princettia Hot Pink'

'Princettia Pure White'

'Viking Cinnamon'

'Winter Rose Marble'

'Ice Punch'

'Luv You Pink'

'Autumn Leaves'

'Strawberries & Cream'

'Christmas Glory Pink'

'Princettia Max White'

'Pink Sparkle'

'Jingle Bells'

​Plant Selection
Selecting a fresh poinsettia is key to its longevity. Look for deep green healthy firm leaves with no insects on the underside. But most importantly inspect the centre of the ‘flowers’. Those bright red petals are not petals at all, but bracts, which are modified leaves. The flowers are the small yellow structures in the centre that resemble little chicks looking up from a nest. They should be plump and happy, not withered nor missing.

Poinsettia flowers are small, green, with yellow and red markings.

The central flowers resemble little chicks.

This poinsettia is past its prime as all the flowers have died and dropped off.

Flowering
A happy poinsettia will keep its colourful bracts for many months. They are great houseplants even if they don’t don their colourful bracts. If you want them to re-flower, trick them into thinking they are in Mexico. Poinsettias are short-day plants, which means they need darkness for 14 hours per day for 6 to 10 weeks in order for them to blossom. To initiate flowering, place them in a cool closet that receives no light whatsoever and keep the door closed for 14 hours. Bring it into the light during the day in a full sun location.

Inside the Botanical Building, Balboa Park, San Diego.

Poinsettia's colourful bracts are not petals, but modified leaves.

Hardiness
Poinsettias are a tender plants that grow from Zones from 9 to 11 so they are often used as temporary houseplants in northern climates. If you live in a subtropical to tropical location, poinsettias are an excellent shrub or small tree for the garden. Place it in full sun, but away from any lights at night, including porch and street lights as that will deter flowering. Protect with sheets or burlap when temperature dip below 10°C (50 °F).
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Flowers from a wild poinsettia.

Poinsettias are loose open shrubs when grown outside in frost-free areas. This colourful specimen flowers on cue in December at The Huntington, San Marino, California.

Native poinsettias aren't fancy as their hybrid cousins, but they are still quite stunning.

​Indoor Care
Since plants are tender, protect from frost even when bringing them home from the store. Place in a paper bag or cardboard box and bring indoors immediately. When inside, select a bright location away from drafts and heating vents. A sunny window is ideal, but keep it away from the windowpane to prevent tissue damage. Close the drapes at night to reduce chilly drafts.
To prolong flowering avoid temperatures over 23 °C (74 °F). Ideally, daytime temperature should be 18 - 22°C (65-73°F) with cooler temperatures at night from 15 - 18°C (60 to 65°F).
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Keep soil moist, but not saturated. Overwatering is a common poinsettia killer. Allow it to dry slightly before watering but before wilting, as it will quickly defoliate. Water with lukewarm water, not cold, and discard any that remains in its drainage tray after 10 minutes. 

Balboa Park, San Diego

A poinsettia display, Balboa Park Gardens, San Diego.

By spring, poinsettias need some TLC.

Repotting
After new growth begins in spring, repot into another container one size larger. Gently loosen roots and plant in fresh potting soil, a slow release fertilizer and bone meal. Cut back all stems by one-third just above a node (bud). Wear gloves when handling poinsettias, as their milky sap can be quite irritating. Water after repotting and mist after pruning. To increase bushiness, in August cut the stems back again by ¼ or just pinch off the stem ends and mist. If you want the plant to flower, avoid pruning after early September. 

Making it Flower Again

​To initiate flowering, on October 1st, place poinsettias in a closet with a light on a timer. Set the timer so the light comes on from 8 a.m. to 5 p.m. daily. Don’t open the closet any other time as poinsettias need uninterrupted total darkness. Keep the soil slightly moist with half strength fertilizer mixed in. Remove the plant from the closet during the last week of November. Flower buds should be visible. Place in a sunny window. Good luck! 

Toxicity?
​It’s a misconception that eating poinsettias is lethal, however, its milky sap can irritate some people’s skin, so it’s best to wear gloves when touching your poinsettia. ​