For the past few years now, mini-poinsettias (Euphorbia pulcherrima) have been popping up here and there in garden centers in the weeks preceding Christmas: only about 4 inches (10 cm) high with only 5 to 10 leaves and crowned with a single inflorescence composed of red, pink, white or green bracts, they are so cute you’ll find it hard to resist buying one, especially since their price is generally quite reasonable. But they rarely live more than a week or two once you bring them home. Why do they kick the bucket so quickly?
Not a Real Miniature
It’s important to understood that these mini-poinsettias don’t come from some new line of genetically dwarf poinsettias. They’re classic Christmas poinsettias that have been miniaturized by rather spartan treatment. In a sense, they are incredibly stressed-out plants! Under normal circumstances, they should easily have been 5 times larger.
To produce them, growers take rooted cuttings of standard poinsettia and force them, especially by exposing them to short days, to bloom well before their time. And to prevent the poinsettia from growing normally, they restrict the amount of available potting soil to the minimum necessary for the survival of the small plant. Think of it a bit like the old Chinese tradition of binding a women’s feet to keep them tiny. It works, but leaves the plant weakened.
You see, miniaturization is not the only result of this treatment. There is also a watering problem. The tiny bit of potting soil available is pretty much filled with roots and holds little moisture. And the result is that the plant dries very quickly, even after a thorough watering. Thus, after two or three days in your home, the plant is often already in a severe state of water stress… and death can follow quickly if you don’t water it immediately.
How to keep one alive
To keep these mini-poinsettias alive, you’ll have to break one of the golden rules of indoor plant care. You’ve certainly heard that you should never leave a plant soaking in water after watering, that this necessarily leads to decay, and therefore that you should always empty the plant’s saucer 15 to 20 minutes after watering. Well, for once, pay no heed to that rule. If you want to keep them well-moistened, it’s all right to let these mini-plants soak in a thin layer of water. Then as soon as this water is absorbed or evaporates, water again, always maintaining that thin film of water in the saucer. If the air in your home is dry, you may have to add a little water – although maybe only a spoonful! – every day.
Obviously, since these poinsettias are living plants, they must still be given at least minimal lighting (they actually prefer intense light, but without direct sun in the middle of the day) and temperatures above 50˚ F (10˚C). High relative humidity will also help ensure that your plants won’t dry out, allowing you to space out waterings to once very 2 or 3 days.
Still, always check before you water: it’s only when you don’t see at least little water in the saucer that you have to water again.
Note that it is not necessary to fertilize mini-poinsettias during their stay in such a tiny pot. Your goal at this point is just to keep the plants in the state in which the grower sold them to you, that is just barely alive, not to stimulate growth.
Some growers sell their mini-poinsettias not in simple plastic pots, but in a waterproof cache-pot, that is, a decorative container with no drainage hole. If you lift the plant, you’ll discover that it is indeed planted in a small but otherwise normal pot with drainage holes (sometimes called a grow pot), but that the pot is suspended above the bottom of the cache-pot, thus creating a reservoir (watering well) that can hold water.
You’ll also see that a synthetic fiber wick hangs down from one of the pot’s drainage holes and into the water at the bottom of the well. Thus, the plant can “drink” all it needs without actually soaking in water, since moisture moves up the wick by capillary action, making sure that, as long as the reservoir is never empty, the plant won’t lack moisture.
Sometimes you’ll see roots growing down into the reservoir as well. If so, just ignore them: they’re the plant’s way of better ensuring it never dries out.
These “self-watering mini-poinsettias” are more expensive than mini-poinsettias sold in ordinary plastic plots, but are easier to keep alive because it is much less likely they’ll run out of water.
Watering a Self-Watering Plant
It may sound like an oxymoron, you still have to water a self-watering mini-poinsettia. The cache-pot’s watering well is not very deep and the tiny plant’s needs are very large.
But you don’t just water a plant with a watering wick any old way: you have lift its pot out of the cache-pot and check that the well is dry or almost dry. Then pour about ½ inch (1 cm) of water into the well before putting the pot back in place. In other words, you water the well, not the plant.
Never let the wick dry out completely. Otherwise, it may no longer be effective. If ever you find not only that the well is completely empty, but that the wick is dry to the touch, fill the well half full of water and insert the pot into it, thus leaving the plant’s root ball actually soaking in water. After 30 minutes, the wick will have been reactivated and you could empty any surplus water, bringing the water level back to its usual ½ inch (1 cm) level.
Nobody claims you can maintain a mini-poinsettia forever. It’s definitely a temporary plant, and after two or three months, the plant really will begin to fall apart, losing leaves and bracts. Even growers who produce them gently suggest you dispose of yours after Christmas and I agree: the laidback thing to do with this little plant is to put it out of its misery and toss it in the compost.
You want to try to keep yours going anyway? Well you can, but not as a mini-plant. Instead, sometime early in the New Year, first cut off its inflorescence (beheading it will redirect its energy to growing roots and stems rather than just maintaining aging bracts), then plant it in a bigger pot: a 4-inch (10-cm) pot should be fine to start with. (Never go from a small pot to a very large one too quickly; that can lead to rot). Use ordinary potting soil. Now begin watering it the way you would a normal houseplant, that is, by completely soaking the root ball and then waiting until the soil is a bit dry before watering again.
You can also start fertilizing it from about March onwards.
With this new treatment, the plant will grow considerably, probably producing several branches and larger leaves. During the growing season, moreover, it may be necessary to repot it a second or even a third time, because the plant will grow greatly in size. And in the fall, you’ll have to give it a short-day treatment in order to get it to bloom again.
Your poinsettia, of course, will no longer a mini, but a normal size poinsettia, with many more flowers and will, moreover, be much easier to maintain.
The mini-poinsettia: a bit of a challenge, but if you can’t resist its charms, at least you now know how to keep it alive throughout the holiday season!