GARDENING:
Poinsettias make for beautiful Christmas decorations.
Native to a small area of central Mexico near the present-day city of Taxco, poinsettias (Euphorbia pulcherrima) were considered a symbol of purity by the Aztecs as far back as the 13th century. The Aztecs also used poinsettia extracts as dyes and to treat fever.
Poinsettias were introduced to North America in 1824 by Joel R. Poinsette, a southern plantation owner, botanist, gardener and the first USA ambassador to Mexico. This large shrub was soon brought to other tropical countries including some in East Africa. In fact, my first memories of poinsettias are from the early 1960s when I was a teacher in Tanzania. There, they were grown as large hedges six feet tall and four feet wide, functioning in much the same way as caragana on a prairie farmstead, but with considerably more class.
Its close association with Christmas is linked to the fact that the short days of December initiate coloration. The traditional bright red ‘flowers’ are not flowers at all, but modified leaves called bracts. The true flowers are the small, insignificant, yellow ‘pips’ located in the centre of the bracts.
Poinsettias have come a long way. Plant breeders in Scandinavia and California, particularly Paul Ecke, have developed the familiar shorter potted poinsettia we associate with Christmas. Poinsettias have also been selected with a greater range of colour: red (of course), pink, white (= light cream), purple, burgundy, mottled, bi-colour, multicolour and spotted. And within each colour group, there may be several cultivars that differ in maturity date, depth of flower (bract) and leaf colour, flower size and form (e.g. rose form), plant size and overall plant shape.
When picking out a poinsettia, look for a damage-free plant with dark green leaves. If leaves and stems are broken, latex sap from the wounds can stain the bracts. Leaves should cover the plant down to the soil line. Fallen leaves or bare stems indicate poor growing or handling conditions. If the foliage is yellow or spotted, look under the leaves to see if white flies or aphids are present. Bracts should be fully coloured with no green around the edges.
Larger, well-grown plants will cost more than smaller or poorly grown ones. Prices vary according to pot size and the number of stems or plants per pot. Containers may range from six-inch pots to hanging baskets, ‘minis’ suitable for a desk or coffee table, to larger floor pots, often with plants of two or three different colours.
During cold weather, ensure that your vehicle is warm and your new poinsettia is well wrapped. One layer of paper is seldom enough. Ideally, it should be wrapped in several layers of paper and a plastic bag, allowing an air space between. These are tropical plants, so direct exposure to temperatures below 50°F (10°C) is likely to cause cold injury such as leaf drop or blackening.
Once home, remove the sleeve or wrapping carefully by cutting it to prevent leaf or stem breakage. Avoid leaving it wrapped up for more than a few days as ethylene gas may accumulate damaging the plant. If the pot is wrapped in foil, make sure that water is able to drain from it.
Poinsettias do best in a cool room (60-70°F) with a minimum of six hours of indirect but bright light. Avoid placing in direct sunlight or near sources of heat or cold drafts. Properly cared for, a poinsettia should last three or four months. Water thoroughly when the soil feels dry to the touch; water should seep out of the drainage holes. But never allow them to stand in water or dry to the point of wilting.
Contrary to the urban myth, poinsettias are not poisonous; however, some people may develop a rash from contact with the milky sap.
Sara is the author of numerous gardening books including her latest with co-author Bob Bors, Fruit for Northern Gardens, just in time for the gift-giving season.