At this time of year, many gardeners bring in geraniums, fuchsias, impatiens, begonias, etc., which grew in their flowerbeds and tubs during the summer. As these “false annuals” are not as short-lived as the real thing, if we save them from frost every year, they can survive and flower for many years.
However, there’s one “annual” that almost no-one thinks of bringing in for the winter, and yet makes an excellent houseplant. We’re talking about Mountain cabbage tree (Cordyline indivisa), also known as blue dracena or Toi. This plant often adorns the center of flower boxes and other containers, where its narrow, pointed leaves, first upright then eventually arching, add a little height to the arrangement. The mountain cabbage tree is grown solely for its green foliage (or sometimes purple), as its flowers, a large panicle of small white flowers, only appear on individuals that are 10 or 15 years old or more, and even then only under excellent growing conditions.
A Real Tree
Curiously, we think of this plant as an annual, when in fact it’s a tree. The young plants sold to us in the spring are only two years old and have no visible trunk. However, if you bring your plant indoors for the winter, it will become a real indoor tree after a few winters. I’ve seen venerable specimens up to 20 m tall in New Zealand, their country of origin, with impressively large trunks, but don’t worry yours will reach that size in “captivity”. A height of around 1.20 m (4 feet) can be expected after around five years of cultivation. The effect created by a three- or four-year-old plant, with its thin leaves at the top and the base of its trunk gradually becoming bare, is that of an indoor palm. (The mountain cabbage tree, however, is not a true palm, but a distant relative of the lily).
Perhaps the most interesting way to use the moutain cabbage tree during its indoor life is as part of your décor. Place it in a sunny or semi-shaded spot, in an ornamental pot or planter, and you’ll have a very attractive little palm tree. In spring, simply put it back outside, either in the center of a planter surrounded by annuals, repeating the traditional use of this plant, or, when it starts to take on a more tree-like and therefore more imposing form, on its own in a planter. A little “palm tree” on your terrace or balcony? Why not!
If you don’t have room for such a large plant in your living room, or if you’re getting ready to head south for the winter, all you have to do is put your cordyline in the cold room or a cool basement and cut it off: no more water, no more light, no more fertilizer until spring. It will then go dormant, without losing all its leaves. I know someone who keeps his in a slightly heated garage… but it’s a risky treatment, because while cordyline tolerates a little frost (down to around -10°C, 14?), it risks dying in the very cold of winter. In spring, gradually expose it to increasingly intense light and increase watering, and you’ve got a magnificent moutain cabbage tree for your summer garden.
A Few Complications
The mountain cabbage tree is not a demanding houseplant, far from it, but it does sometimes pose certain problems.
Firstly, it is somewhat susceptible to red spider mites, which can turn its foliage yellow. Three or four weekly treatments with insecticidal soap should get rid of the problem.
Finally, the large size it can eventually reach can also cause problems, as it may touch the ceiling in around 10 to 15 years. Rather than drilling a hole in the ceiling to accommodate it, cut off its head (which you can also have rooted): it will soon produce two or three new stems, making an even denser crown over time.
Larry Hodgson published thousands of articles and 65 books over the course of his career, in both French and English. His son, Mathieu, has made it his mission to make his father’s writings accessible to the public. This text was originally published in Le Soleil on September 20, 1997.