Poinsettia are Not Very Tasty
The Poinsettia, a native of Mexico and Central America, is a semi-woody shrub
that grows to about 10' / 3m. It is a member of the Euphorbia family, most of which are almost leafless, succulents. We, of course, all grow it as a flowering house plant usually in a 6" / 15cm pot and typically buy and transport it in the middle of a cold and snowy winter. Once again proving that we, as gardeners, do our best to ignore the natural lessons that Mother Nature tries to make obvious to us. Like all Euphorbia, the Poinsettia has a milky, sticky sap that is quite unpalatable but it is not poisonous to human beings or domestic pets. It is anything but tasty and anyone trying to ingest it should give up fairly quickly and wish they had never started but despite persistent rumours to the contrary it will not actually harm you.
Photoperiodic What's That?
We have made it a huge favourite as a Christmas plant because of its photoperiodic response. That’s a five cent horticultural term that indicates that the plant has an observable response to day length. In the case of the Poinsettia that photoperiodic response is, to flower under the influence of shortening days, making it a plant that flowers naturally at Christmas. At last we listen to Mother Nature.
The reality is that we actually don’t care about the flowers on our Poinsettias. The little yellow cyathium that are found in the centre of the plant are the true flowers and we are primarily interested in the brightly coloured bracts that appear around them. These are naturally red and are what most of us see as the “flower” on our Christmas poinsettias. We should learn to look for the yellow cyathium however, because the presence of these small developing flowers is a good indicator that the Poinsettia we are contemplating purchasing is relatively young and fresh. It the bit of stem above the bracts simply has little brown circles on it, where the cyathium have already bloomed and fallen off, then we should leave that plant on the store shelf.
We can’t let Mother Nature dictate everything to us of course and the plant breeders have taken the small red bracts of the natural species and made them much larger and showier and introduced a range of red, pink, white and speckled colours that make Poinsettia shopping much more fun.
Once you realize the ancestry of your Poinsettia, you will understand that it really does not like that cold dash from the store to the car and it must be wrapped up for that 30 seconds to keep the wintery blast away from its subtropical leaves. You also cannot leave it your cold car while you make several more shopping stops along the way. When it gets home, it continues to have an aversion to drafts and should not be located near a frequently opened door. Despite its membership in a family of succulents, it will not tolerate drying out. The bracts that the plant breeders have worked so hard to make semi-permanent, will stay on a plant that has wilted but they will be sitting on the top of bright green leafless stems. Poinsettia leaves once wilted, rarely recover, so stick your finger in the pot on a regular basis and add water when the soil starts to feel a bit dry. No drafts, regular watering, that’s total Poinsettia care. It’s not even fussy about the amount of light it receives right now.
To Bloom Again Next Year
For those of you who think the Poinsettia story is fascinating enough to make you want to try some horticultural handiwork and get this year’s gift plant to bloom again next Christmas, it is possible. I have done it, to prove that I can and now my preferred method is to return this year’s plant to the composter about late February, when it is starting to look more than a little out of season, and purchase a nice new one in December.
Everyone needs to try a couple of times, so here is what you need to do. Late February, early March, cut the red bracts off and about one half of the green woody stem. This may remove all of the leaves. Don’t worry. Keep the plant, or the 3 sticks in a pot, if that’s what it looks like, in a warm sunny location. Eventually new shoots will appear at several of the old leaf nodes. At this point, start to use a liquid fertilizer, like 20 20 20, about once a month. You are still watering it as soon as the soil surface begins to dry out. When all danger of frost is passed move the plant outside to a location where it will get almost full sun. Remember it is native to Mexico. At this point it will need watering much more frequently and it should be fertilized every second watering. It should grow like the 10' shrub that it is and thus you will need to cut it back once or twice during the summer to retain a reasonably sized plant. You can, of course, move it up to a bigger pot as well.
Commercial growers take the pieces that you are cutting off and root them to start the new plants they will be selling at Christmas. As the first of September approaches the tricky part starts. In Mexico, the shortening days will make them bloom naturally at Christmas. They will not tolerate being outside in more northern climes and must be brought into a warm location where there is as much sunlight as possible. So far, relatively easy. The light from a 100 watt bulb in that room’s ceiling fixture is enough to make the Poinsettia think that the days are not getting shorter. You must keep the plant in as much sunlight as possible but when the sun goes down it must be in a room that is in total darkness. Covering it or moving every night becomes a real test of your horticultural dedication. It is possible but even the most dedicated gardeners rarely do it more than once unless they have a separate greenhouse or other growing area that meets the requirements.
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