Tuesday, December 19, 2017

Keeping Christmas Plants Alive After the Holidays

Maybe you got it as a "hostess" gift, or maybe you bought it yourself to brighten up the house for the holidays; a Norfolk Island pine, rosemary topiary, Christmas cactus or poinsettia. And if you are like 90% of people who buy these plants, the minute the holiday decorations come down they will be headed to that great compost bin in the sky. That's really a shame because most of them make great year-round houseplants, and with a little care can provide many years of enjoyment.

First, a couple of caveats:

​The businesses who grow and market Christmas plants fully understand that the vast majority of people are buying them as a sort of extended cut flower arrangement. Their efforts go into getting them to bloom at the correct time and stay relatively fresh and attractive looking for the 4 or 5 weeks between Thanksgiving and New Year's Day. This impacts the way the plants are potted, fertilized, transported and even the specific varieties grown. In other words, very little thought goes into the long-term health and vitality of the plant, so keeping them alive past January can be a bit of an uphill battle.

Also, Christmas plants are often displayed in discount stores and convenience marts or in parts of home & garden stores where plants are not generally sold, so the employees are often clueless about how to maintain them. You can pretty much assume that a plant bought from a temporary rack at the front of a Walgreens has been stressed by too much or too little water and insufficient light; possibly beyond the point of recovery.

​Generally speaking, if you are going to buy a plant from a "non-traditional" seller, it is better to get it toward the beginning of the season. A few days before Christmas, stores will begin selling these plants at a deep discount, but you need to be extremely careful about buying something that has been sitting in a dimly-lit aisle, likely without water, since Thanksgiving.


Of the four plants we are discussing today, poinsettias are the least likely to survive into the next year. A colleague of mine whose thumb is at least two shades greener is able to keep them alive, but it's hard work and getting them to bloom again is hit-and-miss. Honestly, it's probably more trouble than it's worth, but here goes...

If you are planning to keep your poinsettias, the first thing you need to do when you bring them home -- and this goes for all the other plants as well -- is re-pot them. The soil mixture used to grow the plants is designed for fast growth in carefully maintained greenhouse conditions. It is not intended as a long-term growing medium. Use a high-quality potting soil that drains well while retaining moisture, or make your own by combining equal parts peat moss, compost and vermiculite. Poinsettias are tropicals and require lots of light and water, so keep your plant in a sunny window and water whenever the top of the soil feels dry. In a house with dry winter air, you will need to water frequently; at least 3 or 4 times per week.

In the spring, start cutting back on the water and move the plant to a cooler location like a basement or garage. As summer approaches, cut the stems back 2-3 inches and add a bit of organic fertilizer -- I like Espoma Plant-Tone -- every couple of weeks. Once the temperature reaches the mid 70's during the day and doesn't drop below 60 at night, move the plant outdoors to a partially-shaded location. Continue to water and fertilize. Around the 4th of July, pinch each stem back an inch to promote balanced growth. By mid-August, you should see significant new growth. Pinch these new stems back a half-inch in late August.

Now, here's the tricky part. Poinsettia blooms are triggered by the length of the day. In their native habitat, they bloom after 8-10 weeks getting less than 10 hours of light. If you do the math, you will realize that poinsettias don't naturally bloom at Christmas. To force the blooms, place the plant in complete darkness for 14 hours each day, beginning in early October. By late November or early December you should see new buds. Once these appear, you can leave the plant in a sunny window full-time, and if the poinsettia-gods are smiling you should have beautiful new blooms in time for Christmas.


We go from the most difficult plant to keep alive after the holidays to the easiest. Rosemary is actually a small shrub, a fact that is lost on most non-gardeners until the Christmas season when they are often sold as topiaries cut into the shape of Christmas trees. If you are planning to keep your rosemary as a houseplant, re-pot it as soon as possible after the holidays using a good quality potting soil. Rosemary requires full sun, but is drought-tolerant, so you can let the soil dry out just a bit between waterings. Do not allow the roots to sit in water. In many climates, including here in the North Carolina Piedmont, rosemary will grow as a perennial outdoors. If this is your intent, simply transplant into your herb garden or landscape bed right after the holidays.

Christmas Cactus

A Christmas cactus really is a cactus, although it bears little resemblance to what we traditionally think of as cacti. Native to the coastal mountains of Brazil, they grow wild on trees or rocks with very little soil, poor light and high humidity. They were first cultivated as exotic houseplants in the 19th century and became associated with Christmas in the United States because they are relatively easy to force into bloom in the late fall. After the holidays, re-pot using a soil that drains well. The commercially available "succulent" soils work well, or mix equal parts compost, sand and peat moss. Place the pot on a small saucer filled with gravel and water, refilling the water on a regular basis. This will help keep the plant moist. Water frequently, allowing the soil to drain completely. The plant will thrive in moderate light, but like the poinsettia requires extended periods of darkness to bloom. For Christmas blooms, place the plant in complete darkness for 14 hours each day beginning in mid-October. Having said all that, my mother had a Christmas cactus that grew to the size of a large beach ball over a period of ten years and routinely bloomed in late December without any special treatment whatsoever.

Norfolk Island Pine

The very first houseplant I purchased with my own money was a Norfolk Island pine. It was about six inches tall and I bought it from a display near the front entrance of the Woolworth's in the Sandusky Mall circa 1977. That tree grew to be over a foot tall in my south-facing bedroom window and thrived until I went off to college to 1980 and my mother apparently forgot to water it. Since then, I have bought many "seasonal" Norfolk pines and have yet to recreate the success of that first one. It's a plant that I seem to have difficulty keeping alive much past the holidays, despite doing "all the right things." And here's the reason; remember how I said that growers are more concerned with the plants looking good for 5 weeks than they are with their long-term viability? It turns out that many growers spray these trees with a green colorant to make them more attractive in the stores, and this interferes with the ability of the plant to photosynthesize food over the long-term, essentially starving it. So, be aware that the odds may be against you on this one, and that the first thing you should do if you are planning to keep a Norfolk Island pine is to give it a good washing, preferably outdoors where you can really spray it well. Norfolk Island pines are one of the few trees that respond very well to being misted with cool water rather than room temperature water.

These trees are native to, well... Norfolk Island, which is located off the coast of Australia. They are actually an ancient species that would have been very at home in Jurassic World. The trees grow especially well in high humidity environments, so frequently misting them is important for their overall health. Norfolk Island pines should be watered every week during the summer months so that the soil is kept moist. During the winter months, however, the soil should be allowed to dry out completely before the tree is watered again.The pines grow best in cool daytime temperatures and indirect sunlight, but cannot be grown outdoors in the United States; too cold in the winter in the north and too hot in the summer in the south. When placed in a window, the plant should be rotated periodically so that all sides get equal light and the plant grows uniformly. This is important because these pines do not tolerate pruning.

I hope you enjoyed this primer on Christmas plants. I will be taking a few days off over the holidays and doing some fishing at the coast, so I want to take this opportunity to wish all my readers a Merry Christmas. See you again in the new year!

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