Black lower leaves on an orange spider plant. Photo: M. Larose
Question: My houseplant (I don’t know the name) is not doing so well. Its lower leaves keep drying out and turning black. What to do?
Answer: Your plant is a bit of a mystery plant. It’s been on the market for a few years now, but no one seems sure of its real name.
We do know that it’s a spider plant (Chlorophytum), but it certainly isn’t the classic spider plant (C. comosum) that generations of gardeners have come to know and love. It has noticeably wider leaves, bright orange petioles and there are no trailing stolons. Thus, it never produces “babies,” only a central rosette.
Among the names I’ve seen bandied about are Chlorophytum orchidastrum, C. orchidantheroides, C. amaniense and C. filipendulum amaniense, plus it is certainly not a straight species, but a cultivated variety (cultivar) with improved orange coloration. Among the cultivar names I’m seeing are ‘Fire Flash’, ‘Mandarin Orange’ and ‘Green-Orange’.
My guess is that, when the smoke clears, the correct botanical name will probably turn out to be Chlorophytum orchidastrum, while the cultivar name seems likely to be ‘Fire Flash’. Certainly, the very serious Plants of the World online, run by the Royal Botanical Gardens at Kew, offers a file on a very similar plant under the name Chlorophytum orchidastrum, as the image above shows. You can see for yourself here.
Old Leaves Die: That’s Life!
The blackening of the lower leaves on this plant is natural: the oldest leaves, those at its base, quite simply die of old age and are replaced by younger ones at the top of the plant.
In fact, your plant looks very healthy overall; there is even a flower stalk in the center and normally an unhealthy plant doesn’t flower.
However, to keep the lower leaves alive longer, you can offer it the best possible conditions: medium to intense lighting with protection from direct summer sun, high atmospheric humidity during the winter months and potting soil that always remains just a bit moist.
Mineral Salt Buildup
Having said that, I nevertheless see that you have cut off the tips of several leaves, which makes me think there is another problem: a buildup of harmful mineral salts.
Like its cousin, the classic spider plant, the orange spider plant has trouble with tap water, which is often too rich in minerals—calcium, magnesium, iron, fluoride, chlorine, etc.—for its taste. Some people mistakenly believe that by letting water sit in a watering can overnight these minerals will evaporate, but in fact, that concentrates them instead and makes the situation a bit worse, although only marginally so.
If you can, water the orange spider plant with rainwater, dehumidifier water, or distilled water instead of tap water, as they contain few harmful minerals.
If you can’t, get into the habit of leaching the potting mix every 2 months or so. To do so, set the pot in the sink and pour a solution of fresh water and white vinegar (about 200 ml of vinegar per liter of water) over the potting soil and let it filter through. Then, allow the contaminated water that comes out of the pot’s drainage holes to flow down the drain: this helps dissolve the lime (calcium) that has accumulated in the soil.
Another solution is to repot the plant at least once every two years, completely replacing the potting mix as you do so. That way you’ll remove the contaminated mix and replace it with fresh, largely mineral-free potting mix.
And finally, don’t fertilize this plant too heavily. The orange spider plant isn’t a very greedy one at any rate, so an all-purpose fertilizer applied at 1/8 of the recommended rate—and only during spring and summer—will be more than enough to meet its needs.
Finally, of course, do remove the blackening leaves at the base of your plant by pulling or cutting them off. That will immediately give it a prettier and healthier appearance.