Let’s say you just received a poinsettia as a gift, or bought a couple for decoration around the house, and you don’t know much about them. How should you take care of it? Or them?
First: they are tropical plants, like your houseplants, so they don’t like cold temperatures. Temperatures in the high 60’s or low 70’s are the best. If it’s say, in the 30’s, don’t buy it on the way to work and leave it in the car all day.
If you get it from a garden center or florist, then it will probably come in a protective paper (or sometimes plastic) covering called a plant sleeve. This is to give it some protection from cold, breakage, and to make it easy to carry. You should remove the sleeve as soon as you get it home.
As part of what plants do to pass the time, they give off a wee bit of a gas called ethylene. In a confined space (like a plant sleeve, or a shipping box) ethylene causes poinsettias to droop. It’s a permanent condition called epinasty. The plant looks like it needs water. If you see a display of poinsettias in a store and they all look “tired,” they have probably been sitting in boxes for too long—say, 24 hours.
Sooo…if you are buying a poinsettia to give as a gift, take it out of the sleeve until you are ready to deliver it—it will look nicer. Be careful taking it out of the sleeve; poinsettia stems are very brittle, and shaking them around will cause stems to break. Best to cut the sleeve off.
Light: they will do best in a bright spot, but frankly, you can put them just about anywhere. The lower the light, the sooner the lower leaves will turn yellow and drop off; but the “flowers” will still look pretty good even if stuck in a corner. Especially if you are looking down at the top so the now-bare stems don’t show.
Speaking of the flowers, the part we think of as flowers, the red parts, are modified leaves called bracts. The actual tiny flowers are in the center of the ring of bracts. A sign of “freshness” is that the flowers or buds are still there when you buy the plant. On an older plant, the flowers will drop off, leaving just the colorful bracts. In my experience, when that happens the color of the bracts on the red varieties tends to fade a bit. The flowers will drop in your house, but you may as well try to buy one with the flowers still on the plant, especially early in the season.
Water: poinsettias should be allowed to dry some between waterings. This can be difficult if it’s in a decorative ceramic pot, or in foil or a pot cover because when you water the plant the excess water has no where to go, and the soil goes “sour” from lack of air. It’s a pain, but I recommend carrying the poinsettia to the sink, removing the foil, and watering it in the sink. Run some water into the soil, go away and let it drain for 10 minutes, then return the plant to the foil or decorative pot or basket. Or you could just discard the foil/pot cover which I think actually detracts from the beauty of the plant. Gilding the lily, and all that.
Potted poinsettias are pinched as they are produced to keep them short and to encourage branching and fullness. (By pinching, we mean that the top of the shoot is removed. It is snapped off by hand, or “pinched” off.) In the earlier days of poinsettia production, say in the mid-1900’s, the poinsettia varieties of the time didn’t respond well to pinching; they grew tall and straight and also lost their leaves more quickly, leaving these sort of ugly stems with the flowers at the top. Florists put large sheets of foil on the pots to cover the pot (in those days, clay and probably coated with slippery green algae) and the ugly stems. Today’s pot covers date back to this.
You should be able to tell if your poinsettia needs water by lifting the plant. If it’s relatively heavy, it doesn’t need water. If it’s relatively light, it does. On a typical poinsettia in a 7 inch diameter pot, I find in my fairly cool house that I only have to water every 5 days or so.
If the plant is wilting and the pot is light, it needs water. If it’s wilting and the pot is heavy, you likely have an overwatered plant with dead roots. (The roots probably have an infection of a fungus called Pythium; they are pythed off.) You water and it stays wilted, because the roots are dead; nothing you can really do but discard it.
Getting your poinsettia to bloom again: it can be done, but don’t waste your time. It will never look anywhere near as nice as a new one from a greenhouse. Better to start off fresh next year.
by Larry Hurley, Behnke horticulturist