Cacti: August Houseplant of the Month


Whether it’s their trendy geometric shapes or their air of unapproachability, cacti are exciting houseplants that have a big impact on an interior decor and often live alongside their owners for decades. This classic plant’s comeback is particularly due to its (undeserved) reputation as needing no care as well as its unusual appearance.

Origin of Cacti

Distribution map of cacti in the wild. Ill.:

The spiky plants that we call cactuses or cacti (both plurals are acceptable) are from the Cactaceae, a large plant family native throughout much of North and South America, with a strong concentration in Mexico. The plants mainly grow in dry or desert regions where they have adapted brilliantly to the extremely arid conditions and positively thrive where most other plants would have trouble surviving.

The name cactus is derived from the Greek word “kaktos”, which means “spiky plant”. Every cactus is a succulent, but not all succulents are cacti. What cacti share with other succulents is the ability to store moisture in their thick fleshy stems. These reservoirs are used to bridge periods of drought.

Cactus roots may be confined in a pot in culture, but in the wild, they are far-reaching and are usually found just below the surface in order to slurp up as much water as possible during those rare rainy periods that allow them to grow.

Notice that, with very few exceptions, cacti have no leaves. They lost them as they adapted to growing under conditions of great aridity. Instead, they carry out photosynthesis via their green stems. The cactus’ outer skin has a layer of wax that minimizes evaporation.

The woolly bumps on cactus stems are areoles. Only cacti have them. Photo: Steve Cook @Polypompholyx

What distinguishes cacti from all other succulents is that their stems bear areoles: the place where the leaves should actually be. These look like fuzzy little pads usually placed quite symmetrically on the stems. From these areoles grow spines, long hairs, new stems and, eventually, flowers. No other plant has areoles and looking for them is the best way to tell a cactus from other stem succulents, like euphorbias.

Cacti have been cultivated for centuries, as outdoor plants in mild climates, but elsewhere mostly as houseplants. That said, there are hardy cacti, some tolerant of extreme cold, but most cactus species are best grown as indoor plants everywhere outside of the very mildest climates.

What to Look for When Buying Cacti

With cacti, there’s lots to choose from in just about any garden center.
  • Price is largely determined by size. Small cacti are less expensive than large ones as they cost less to ship. Some cacti are naturally small and will always remain so; others will grow considerably over time. If you want a small cactus that will grow large, a young columnar cactus (see below) would make a good choice.
  • Age is also a factor in pricing. Cacti that take years to grow to a saleable size will cost much more than fast-growing cacti. That often explains why two similar-sized cacti can have such a difference in price.
  • Check that the cacti are free of mealybugs on both the plant itself (the body) and the root system. With their woolly white waxy coating, these oval sap-sucking insects are one of the most common pests in cactuses and are difficult to get rid of. Leave infected plants in the store.
  • Also check for red spider mites (looking like dust particles moving over fine webbing), aphids, scale insects and thrips. 
  • Check for damages to the plant’s stem and make sure that the root system is intact. If the plant has been kept too wet for a long time, it may show a soft spot at the base of its stem, the first sign of rot caused by fungi and bacteria. Avoid such plants.
All these flowers were glued on to push sales. Photo:
  • Look at any cactus flowers with suspicion. Often such blooms are simply dried strawflowers glued onto the stem and the glue used permanently damages the plant. To check, gently push the petals upward and check underneath the blossom. Real cactus flowers will be attached to the main stem by a shorter, usually spiny stem, not by glue.
  • If you want a cactus that will bloom readily, ask the clerk to help you choose. Many cacti are reluctant to bloom indoors.
Spray-painted cactus are now widely available, unfortunately. Photo: pentagrambunny,
  • Be wary too of plants with oddly colored spines. White, golden yellow, gray and brown are normal spine colors, but purple, blue, orange, fluorescent yellow, etc. are not. It has become popular to “enhance” cacti by spray-painting them. This is harmful to the plant and such plants should be left in the store.
Cactus are very unhappy in a terrarium setting and usually die slowly. Photo:
  • Avoid cacti planted in terrariums and bell jars. With no drainage hole, they are almost impossible to water, and they hate the high humidity and poor air circulation found there. They usually die slowly over a period of several months.
  • Spiny cacti can be hard to handle. Have the clerk handle and wrap your plant for you. 

Cacti Range

With some 1,800 species, the range of cacti is enormous and extends from tiny sleek shapes through bizarre massive pillars, and from soft gray hairs through to big sharp spines. Many cacti are sold in mixed trays, particularly the smaller sizes. The species that are most commonly sold by name are EchinocactusFerocactusGymnocalyciumOpuntia and Mammillaria.

Cactus can masquerade as other succulents, but their areoles give them away. Photo:, montage:

Succulent Euphorbia species closely resemble cactuses and are often sold in the same mixed trays. It’s easy to spot the difference: euphorbias thorns grow directly out of the green body, while those of cactuses they grow out of the areoles, the fuzzy bumps mentioned above. Also, many euphorbias have small leaves while cactus rarely do.

Desert Cacti or Forest Cacti?

Desert cacti. Ill.:

Most cacti are desert dwellers or at least adapted to intense sun and arid conditions. These usually have the thickest stems, abundant spines or hairs, and will require full sun and well-spaced watering indoors. They are listed below as (dc).

Forest cactus. Photo:

Another group of cacti lives in forests in the wild. Most are epiphytes (grow on tree branches) and have thin or flattened branches, few or no spines and a trailing habit. In culture, they require less light and more regular waterings, more like a spider plant than a typical cactus. Below, they are indicated by the abbreviation (fc).

A Wide Range of Shapes

Cacti can be classified by genus, origin or shape. The following groupings can give you an idea of their shapes:

Prickly pear cacti (Opuntia spp.).
  • Prickly pears, also called beavertail or bunny ear cactus (dc): They have flattened, paddle shape pads. Only the genus Opuntia has this form. They have either long spines or apparently no spines at all. Beware, though, as their seemly innocuous areoles hide tiny spines called glochids that break off and penetrate the skin.
The Peruvian apple cactus is a typical columnar cactus (Cereus repandus). Photo:
  • Columnar cacti (dc): Upright shapes that start small and develop a real pillar shape later (Pachycereus, Cereus and others).
Various mammillarias (Mamillaria spp.) with real flowers. Mammillarias usually bloom quite readily after a cold, dry winter. Photo:
  • Globe cacti (dc): Attractive globe shape. May grow individually or in columns. (EchinocactusMamillaria).
Various mistletoe cactus (Rhipsalis spp.): Photo:
  • Trailing cacti (dc and fc): With long stems arching down (AporocactusRhipsalis).
Orchid cactus (Disocactus ackermannii, formerly Epiphyllum ackermannii). Photo:
  • Orchid cacti (fc). Epiphytic cacti with spreading, trailing, triangular or flat stems, usually spineless (EpiphyllumSelenicereus). Grown for their huge flowers (seasonal).
Thanksgiving cactus (Schlumbergera truncata cv). Photo: Peter Coxhead, Wikimedia Commons
  • Holiday cacti (fc): Arching, flattened, spineless stems bearing bright flowers at Thanksgiving, Christmas and Easter (Schlumbergera).
Brain cactus ((Mammillaria elongata ‘Cristata’). Photo:
  • Crested cacti (dc): Mutated cacti taking on a brainlike shape (Mammillaria elongata ‘Cristata’ and many others).
Albino forms of Gymnocalycium mihanovichii friedrichii grafted onto a photosynthesizing cactus. Photo:
  • Grafted cacti (dc): Two species grafted onto one another. Often the top cactus (Gymnocalycium), brilliantly colored (red, pink, orange, yellow, etc.) is actually an albino and can’t grow on its own.

Care Tips 

Severely etiolated cactus desperately trying to tell its owner it needs more light. Photo: anskuhh s,

Cacti are often said to be easy-to-grow plants that will thrive anywhere. This myth is largely based on their capacity to “hold on” for months, sometimes even years, even under the most inappropriate conditions. Even as the owner is pleased with the results, the plant is often dying, living on its reserves, but not clearly showing its distress. When death finally comes, it often stuns the owner.

If treated as a throwaway plant, designed to be tossed into the trash when it stops looking good, a cactus can be placed anywhere, sun or shade, in heat or in cold. Water it when you feel like it or not at all. If you find that acceptable, why not buy a plastic plant? It will last longer and won’t have to suffer a lingering death.

Here are some tips on how to really keep cacti happy and healthy:

Most cactus have to be grown in front of a sunny window in order to thrive. Photo:
  • Desert cacti require intense light (full sun), especially spiny and hairy ones. Forest cacti, like holiday cacti, tend to be better choices for lower-light situations. Given the proper light, most cacti are easy to maintain and can live for decades.
  • But proper watering is also necessary. Desert cacti will not tolerate overwatering and have to be allowed to dry out thoroughly before watering again. So, benign neglect is best. If you’re not sure whether a cactus needs watering, it probably doesn’t. Lift the pot to tell: it will be considerably lighter when it is fully dry. Or use a moisture meter, watering only when the dial is well into the red zone (dry). 
  • Water forest cacti more regularly, although still only when the soil is dry to the touch. You can water them when the soil is barely dry rather than waiting until it is bone dry.
  • When you do water, do so thoroughly, soaking the root ball, although never letting the plant sit in water. Giving just a spoonful or two of water at a time is a common error and causes long-term stress. 
  • Cacti can tolerate hot, sunny spots in the summer and also thrive outdoors on the patio or balcony. They prefer cool conditions, although still with intense light, in the winter. A cold, dry winter, down to nearly freezing, can encourage some desert cacti to bloom.
  • Cactus are very tolerant of negligence and can be left on their own with no care at all on a bright windowsill when you’re absent. All will tolerate at least a month without watering; desert cacti, often 5 months or more, making them an ideal choice for Snowbirds.
  • If the plant needs repotting, use a well-drained, fairly nutrient-poor soil. Special cactus soil is available for this. Since cactus don’t tolerate overwatering, the pot must have a drainage hole.
  • Place the prickly cacti in a safe place if there are children or pets around. Those spiny can be nasty!

Display Tips

Cactus gardens are a fun way to grow cacti.
  • One cactus is never enough! The plants speak to the imagination best if different species are displayed together.
  • Cacti make great choices for a student room or an office, as they can tolerate long periods of negligence.
  • The various sizes on offer—from mini to massive—make them ideal gifts.
  • Cactus gardens combining various species are attractive and exotic. They do best in open bowls rather than terrariums.
Artisan pots can make cacti really stand out. Just make sure they have a drainage hole!
  • Cacti can be used both in traditional interiors and in a modern setting. A folkloric look is the bang-on trend and doesn’t need to be restricted to South American decors. Artisan pots with folklore patterns and colors create a cheerful setting for the rather stoical cactus. 
  • The plants can also be used for certain summer or holiday themes (beach, Mexico, indoor rock garden, etc.).

Enjoy your cactus and … long may it live!

Text adapted from a press release by
Unless otherwise mention, photos also by
Styling by Elize Eveleens, Klimprodukties

15 Not-So-Easy Houseplants


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This peace lily (Spathiphyllum) is suffering from chronic underwatering: a typical problem with this species. It’s not as easy to grow as many people claim. Source:

In preparing yesterday’s article, 15 Easy Houseplants for Beginners, I, of course, took a look at other websites to see what they suggested. (No, that’s not plagiarism: it’s called “research!”) But I must admit I was surprised by some of their suggestions, sometimes even horrified!

After all, the purpose of writing such a piece is to showcase indoor plants that are particularly easy to grow, ones that even the most fledgling gardener could grow without difficulty. But these other lists included plants that I would never have thought to include among easy-to-grow plants, plants whose flaws rather make them a challenge to keep alive unless special precautions are taken. In fact, plants I would normally warn people about.

Let’s take a look and see.

Why Do These Not-So-Easy Plants Fail?

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Good light is very rare in most homes, leading plants to suffer from etiolation, like this unfortunate Aloe vera. Source:

Sometimes the problem is simply that the plant needs really good light. I would never recommend such a plant as an easy-to-grow houseplant, not considering the horrible indoor lighting conditions most people have. Even fairly experienced indoors gardeners tend to overestimate the quality of light they have available to them. Imagine beginners!

The average dwelling is not a greenhouse, with light from above and on all sides. In most rooms, it only comes from one side, through a vertical window. And most readers of this blog live in temperate climates, where sun may be fairly abundant indoors in the summer, but miserably lacking in winter, what with short days and weeks of cloudy conditions. So even right in front of your largest window, there is often not enough light for many plants, especially if it’s on the north side of our home (in the Northern Hemisphere, that is). Imagine what conditions are like in the back of the room! That’s why, in my opinion, only plants that can tolerate low light can be considered easy-to-grow houseplants.

And they must also be not only capable of putting up with low light, but of doing for long periods. This belief that some many commercial nurseries seem to have—that 8 weeks is an acceptable lifespan for a houseplant (see The Life Expectancy of Houseplants) and therefore that a plant that can last 8 weeks in near darkness can be classified as a low-light plant—is just nonsense! According to my way of thinking, to be shade-tolerant, it always has to be able to grow and even thrive in shade, not just for a few weeks, but years.

In other cases, not-so-easy houseplants are too sensitive to dry air for the average home, too subject to insects or diseases, naturally short-lived or have special requirements that go beyond regular maintenance and thus complicate their care. If you can’t just resume a plant’s care by saying “put it in your living room and water it when its soil dries out,” it’s not an easy-to-grow houseplant.

15 Not-So-Easy Houseplants

Here are 15 indoor plants that appear on other people’s list of easy houseplants. In general, no, they aren’t extremely difficult to grow, at least not for a gardener with experience, but, for one reason or another, you just can’t expect a beginning gardener to succeed with them.

1. Boston Fern (Nephrolepis exaltata ‘Bostoniensis’ and other cultivars)

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Boston fern (Nephrolepis exaltata cv). Source:

This fern tolerates dry air better than most other ferns, which is great, but is far less tolerant of shade. In fact, it really only does well when put in a pretty sunny location … and that’s not what most people do.

The Boston fern used to be a far easier houseplant before the middle of the last century, one our grandparents often grew to astounding sizes. What changed? Our indoor environment! We heat our homes more, yet this plant likes a cool winter. As a result, it often gets smaller and thinner over time instead of plumping up like a happy houseplant should do.

2. Bromeliads (Aechmea, Guzmania, Tillandsia, Vriesea, etc.)

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Various bromeliads. Source:

These plants are totally charming and can last for months in a typical house. But usually, they’re sold in bloom … and that’s a problem, because they die after flowering! And it’s just plain unfair to hoist a soon-to-die plant off on a rank beginner.

True enough, with rare exceptions, bromeliads will produce at least one “pup” (offset) before they go, a pup that will flower in its turn … a few years down the road! Understanding that is a lot to ask of a novice gardener. They’re more likely to become discouraged when they see the mother plant deteriorating bit by bit.

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Air plants (various species of Tillandsia) need such different care from other houseplants, they need to be treated separately. Source:

As for air plants (Tillandsia spp.), a subgroup of bromeliads, their situation is somewhat different. First, they are rarely sold in bloom, but rather as unrooted plants you’re supposed to hang from the ceiling or deposit on or glue to an indoor arrangement of some sort. The fact that they need totally different treatment from any other houseplant automatically makes them complicated. They have to be watered, not by humidifying the soil they grow in (because they don’t grow in soil!), but by soaking them in water or spraying them regularly. Of course, they also need bright light and air movement. I wouldn’t say air plants are necessarily difficult to grow, but they aren’t easy either. If you want to know more about growing air plants (Tillandsia), read How to Make Your Air Plants Thrive.

3. Butterfly Palm or Areca Palm (Dypsis lutescens, syn. Chrysalidocarpus lutescens)


20180127N Dypsis lutescens

Butterfly Palm (Dypsis lutescens). Source:

This plant’s susceptibility to spider mites makes it a challenge to grow. It often breezes through summer in fine shape, then, with the arrival of fall and drier indoor air, spider mites show up and soon start to take over. You never seem to be able to get rid of them entirely!

The butterfly palm is not the only palm with this problem, by the way. As a result, few are good choices for beginners.

4. Cacti and Succulents

20180127D Succulentes

Cactus and succulents: great choices if you have full sun, but most aren’t given nearly enough light and go downhill slowly once you bring them home. Source:

There are hundreds of houseplants in this category and most are not at all hard to grow … if you have a lot of light. Indeed, most even prefer full sun (there’s not much of that in the average home)! Sadly, our homes are simply much more shaded than most people imagine. As a result, I see cactus and succulents in various states of decline wherever I go. Yes, they may be still alive, but barely.

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This is not a happy cactus (Opuntia). It’s severely etiolated due to insufficient light. Move it to a sunny window, fast! Source:

Of course, among the wide variety of succulents, there are some that tolerate some shade and are therefore better choices for beginners, such as aloes (Aloe spp., including A. vera), haworthias (Haworthia spp.), gasterias (Gasteria spp.), succulent euphorbias (Euphorbia spp.) and, of course, the oh-so-popular jade plant (Crassula ovata) … but they still need a location that receives at least 5 hours of indirect light per day, therefore a location very close to a window. You have no idea of how many very sad, floppy jade plants I see, alive but struggling, in people’s homes. Their weeping stems seem to say, “Please put me out of my misery!”

Also, many beginner gardeners lose their succulents over the winter because they water too much. When you grow succulents, it is very important to let the soil dry out before watering again. Doubly so when light is low, as is the case in winter. Often, at that season, cacti and succulents only need to be watered once a month, yet the average indoor gardener tends to water everything they grow once a week. You can just feel the rot settling in!

5. Calathea (Calathea spp.)

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Calathea zebrina. Source:

This is a prime example of a plant that “holds” for several months, especially when you buy it in the spring or summer, but ends up going rapidly downhill in the winter. It’s supersensitive to dry air (a common problem indoors in winter) and really has a hard time dealing with the lower light winter brings. The result is a great plant that soon goes bad.

6. Croton (Codiaeum variegatum)

20180127I Codiaeum variegatum

Most crotons (Codiaeum variegatum) drop their leaves one after the other when you move them into your home and soon come to look like this. How could anyone possibly call them easy to grow? Source:

Recommending crotons to beginning gardeners is out and out horrific. This plant has a terrible reputation among gardeners for its ability to quickly go to pieces when you bring it home. The problem is that it simply doesn’t tolerate changes in its growing conditions, so when it goes from the full sun and high humidity of Florida or Costa Rica to a dingy apartment where the air is drier than the Sahara, it starts losing leaves. And more and more fall off as time goes on. Now, if you know how to properly acclimatize it, you can get it to adapt perfectly well to average indoor conditions, but it’s hardly a plant you’d want to entrust to a beginning gardener! Shame on anyone who promotes the croton as an easy-to-grow plant!

7. English ivy (Hedera helix)

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English ivy (Hedera helix). Source:

Typically, this plant is easy to grow in spring and summer, then fall comes and it falls apart. The problem is that when the air gets drier, as it almost always does during the heating season, spider mites appear out of nowhere and quickly kill it. Few plants can be covered with spider mites as quickly as English ivy.

8. Peace Lily (Spathiphyllum)

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Like most peace lilies (Spathiphyllum) sold these days, this one is severely underpotted and will quickly go into decline unless it receives very good care. Source:

Sure, this plant is easy enough in general, but it quickly takes on a wilted lettuce look when it runs out of water and each time it does, the next recovery is less and less successful. It always seems to be drastically underpotted when it reaches your local garden center, which, of course, compounds the problem. Quite often, it must be watered more than once a week just to survive! Repotting it into a bigger pot as soon as you get it home will help, but if you’re one of those people who tend to forget to water every now and then, the peace lily is definitely not a wise choice for you!

9. Norfolk Island Pine (Araucaria heterophylla)

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Severely overcrowded, this pot of Norfolk Island pines (Araucaria heterophylla) won’t likely live very long. Source:

Few Norfolk Island pines survive more than a few months in the average house. Their need for fresh, humid air while our homes are hot and dry in the winter ends up killing them. Plus, the trend these days is for nurseries to stick a half a dozen or so young plants in the same pot so it will look fuller … and that only means there are more roots competing for the water you apply, with fatal results. Under good conditions, and when reduced to one or two plants per pot, this indoor conifer can live for decades. Still, I wouldn’t offer it to a rank beginner!

10. Peperomia (Peperomia spp.)

20180127O Peperomia caperata Emerald Ripple Lazaregagnidze, WC.JPG

One of many types of peperomia. Here, Peperomia caperata ‘Emerald Ripple’. Lazaregagnidze, Wikimedia Commons

There are too many species (over 1500!) of peperomias for me to make more than a vague generalization about them, but even so, many of the commercially available varieties are prone to rot if overwatered … and who doesn’t apply just a bit too much moisture every now and then? Typically, peperomias grow well at first and its owner is very pleased with the result, then, months later, they suddenly keel over and die. It can be quite a shock to see them go from healthy and happy to dead and rotting in just a few days.

11. Prayer Plant (Maranta leuconeura)

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Prayer plant (Maranta leuconeura erythroneura). Source:

Yet another plant that gives encouraging results at first, especially if you buy in spring or summer, when there is more light in our homes and the air is generally humid, but the low light and dry air of winter cause it to die back gradually. By spring, it’s often only the shadow if its former self, if indeed it’s still alive.

12. Rubber Plant (Ficus elastica)

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Rubber plant (Ficus elastica ‘Burgundy’). Source:

It’s unfortunate that nurseries continue to insist that the rubber plant is a low-light plant when, on the contrary, it requires a lot of light, even full sun. True enough, it “holds” quite well in shady spots, sometimes for six months or more, but once it’s used up its energy reserves, leaves start to drop one by one until death ensues.

13. Schefflera or Umbrella Tree (Schefflera actinophylla, syn. Brassaia actinophylla)

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Schefflera (Schefflera actinophylla). Source:

This is the larger of the two common scheffleras, the one with big, shiny, umbrella-like leaves, not the dwarf schefflera (S. arboricola), a much, much easier plant to grow. Like English ivy and the golden cane palm, its susceptibility to spider mites makes it difficult to maintain in good shape for very long.

14. Spineless Yucca (Yucca gigantea, Y. elephantipes and Y. guatemalensis)

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Spineless Yucca (Yucca gigantea). Source:

Generally sold as a small tree with a brown, woody looking trunk with tip cut off and two to four tufts of lanceolate leaves at the top, the spineless yucca is a superb plant, but it shares the rubber plant’s bad habit. That is, it “holds” well, for months at a time, even in shady spots, then, when it has spent all its stored energy, it launches into a long decline. It can sometimes survive (one can hardly say “live”) for two or three years under a typical home conditions, but, unless it’s right in front of a sunny window, becomes more and more etiolated and less and less beautiful over time, with yellowing leaves galore!

15. Weeping Fig (Ficus benjamina)

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Unless it is properly acclimatized, the weeping fig (Ficus benjamina) starts losing leaves and is soon in decline. Source:

Okay, this plant can tolerate the shade and dry air of our homes and can even live decades under such conditions, but, as was the case with the croton, this is only true if you acclimatize it well beforehand. Otherwise, the leaves begin to fall almost as soon as you bring it home and it soon looks dreadful. Many more people manage to kill their weeping fig than succeed in keeping it healthy and happy. Read Stop Your Weeping Fig From Losing Its Leaves to learn how to acclimatize it.

There you go! 15 plants that may be interesting for gardeners who have a bit of experience, but which I would certainly not to offer a wet-behind-the-ears gardener. Definitely not “easy-to-grow houseplants,” in spite of what some websites claim!20180127A Spathiphylium