Plants with Weird Leaves: Leaves That Move

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Some leaves really like to shake it up! http://www.oogazone.com & freedesignfile.com

From time to time, I like to write an article about the oddness of some leaves. Here’s yet another, about plants whose leaves actually move.

Leaves Move All the Time

The truth is, leaves that move are not that unusual. They notably move in the wind, or when touched by rain drops or brushed against. However, there are extraneous movements: the plant isn’t moving on its own, it is being moved. That said, many plants do have leaves that move themselves. You’ll learn more about them by reading the following text.

Movement for Protection

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Resurrection fern (Pleopeltis polypodioides) fronds curl up and look dead when dry, but will green up again when the rains come. Source: apalacheehills.com

Many plants have leaves that curl up or roll down under stressful conditions—drought or cold, for example—but recover afterward. The resurrection fern (Pleopeltis polypodioides, syn. Polypodium polypodioides) can survive without a drop of water for many months, even years, then its apparently dead fronds become completely green and functional within 24 hours after a good soaking. Two other resurrection plants are the rose of Jericho (Selaginella lepidophylla) and the alpine gesneriad ramonda (Ramonda spp.).

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These drooping winter rhododendron leaves will straighten up, uncurl and come back to life when warmer weather arrives. Source: http://www.indefenseofplants.com

As for movement to improve cold resistance, the thick leaves of many hardy rhododendrons (Rhododendron spp.) lose most of their moisture and both curl and hang limply all winter, giving their owners quite a scare, yet recover fully when spring returns. It’s thought this habit helps keep frost crystals from forming and damaging leaf cells.

Turning Towards the Sun

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Unless turned regularly, most houseplants will bend in the direction of the light source, Source: Donnie, http://www.houzz.com

On most plants, leaves will turn to face the direction of the sun, at least to some degree. If you transplant or otherwise move a plant—or even if you just cut an overhanging branch that was blocking the sun!—the leaf will adjust, changing its position, usually quite slowly, over days or weeks. This is particularly easy to observe on a forest edge where most light comes from the side or on a windowsill in your home if you don’t give your houseplants the traditional quarter turn regularly: most of the leaves will clearly orient towards the light. This habit of growing towards the source of light is called phototropism. (Remember that term from school?)

Night Moves

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Prayer plant (Maranta leuconeura) leaves move upward at night, like hands in prayer. Source: Aida F., http://www.pinterest.

Other plants have the curious habits of folding their leaves at night, either upward or downward, a phenomenon called nyctinasty. It’s actually very common in some plant families, such as the legume family (Fabaceae) and the oxalis family (Oxalidaceae). You may have noticed this in clover (Trifolium) or false shamrock (Oxalis triangularis), but the best-known nyctinastic plant is the popular houseplant known as the prayer plant (Maranta leuconeura), whose leaves fold up at night like hands in prayer.

This kind of movement is caused by a hinge-like structure at the base of the leaf or leaflet called the pulvinus (plural: pulvini) that is filled with water during the day, but drains at night, so that the resulting lack of turgor causes the leaf to fold.

Scientists still debate why plants do this.

Plants That Dance

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Carefully watch the fire fern (Oxalis hedysaroides ‘Rubra’)—not this photo but a real plant!—and you’ll discover it’s in nearly constant movement. Source: bluepumilio.com

There are plants that, under the appropriate conditions, take the concept of nyctinasty one step further. They too have pulvini and do close at night, but during the day, seem to be constantly readjusting themselves. The fire fern (Oxalis hedysaroides ‘Rubra’), not a fern at all, is a red-leaved oxalis sometimes grown as a houseplant, one of these “dancing plants.”

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The telegraph plant (Codariocalyx motorius) seen using time-lapse photography. You can actually see it move, but not quite that fast! Source: gfycat.com

The telegraph plant (formerly Desmodium gyrans, now Codariocalyx motorius), is another occasional houseplant with seemly motorized leaves.

Both plants will only perform when conditions are fairly warm and humid, but if you sit in from of one and watch patiently, you’ll see each leaf seems to be slowly moving, giving the impression the plant is lazily dancing. The fire fern will also react to touch, at least to a slight degree, but more about touch sensitive plants later.

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The carambola (Averrhoa carambola) has leaves that move all on their own. Source: biogeodb.stri.si.edu

The tropical fruit carambola or starfruit (Averrhoa carambola), in the Oxalidaceae, likewise has leaflets that both close up at night and move visibly, although slowly, during the day, all on their own … if you watch them patiently!

Response to Touch

Plants that react to touch are certainly the weirdest of all plants with leaves that move. This phenomenon, known as thigmonasty or seismonasty, occurs when something touches or shakes the leaf. And some will also react when you hold a match up to them. This can be incredibly rapid and is certainly visible. Again, all these plants close up at night and, again, it’s pulvinus at the leaf or leaflet’s base that empties rapidly, causing the leaf folding. Studies show that there is even an electrical current that runs between the pulvini on many of these plants, almost like nerves in animals, plus there is also a chemical reaction involved.

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Sensitive plant (Mimosa pudica). Source: worldoffloweringplants.com

The best known thigmonastic plant is the sensitive plant (Mimosa pudica), a legume also known as sleepy plant, dormilona, touch-me-not or shy plant, a decent if usually short-lived houseplant easy to grow from seed … and also a pernicious and quite prickly weed in tropical countries. A light touch will cause a single leaflet of the bipinnately compound leaf to fold inward, a firmer touch will lead to the whole leaf drooping and shaking the plant will cause all its leaves to collapse. If you run a finger down the leaf, the leaflets will close like dominoes, as in the photo below. Yet if you leave the leaf alone, it will recover in just 15 to 30 minutes.

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Mimosa pudica leaf closing. Source: Mimosa_Pudica Hrushikesh, Wikimedia Commons

It’s thought this quick reaction to touch helps prevent foraging by grazing animals. I mean, wouldn’t you stop eating if you thought you were biting into a luscious plant, then the leaves all collapsed after your tongue touched the first one, leaving the plant looking barren, unappetizing and full of (previously hidden) thorns?

M. pudica is the most commonly grown sensitive plant, but there are some 400 other species in the genus Mimosa, both herbs and shrubs, all sensitive to touch to at least some degree. There is even a hardy sensitive plant (zone 5) that can be grown as a perennial, M. nuttallii.

Note that these are true mimosas, not the trees and shrubs often called mimosas and which are actually very different, non-sensitive plants with similar pinnate leaves such as Albizia julibrissin (silk tree) and several acacias, including Acacia dealbata (blue wattle or mimosa).

There are also several species of “aquatic sensitive” (Neptunia spp.) with leaves much like those of the sensitive plant that react to touch in a similar fashion. As the common name suggests, they grow in water or at least under very boggy conditions.

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Little tree plant ((Biophytum sensitivum) has leaves that move. Kenraiz, Wikimedia Commons

Less well known is the little tree plant (Biophytum sensitivum), a small herbaceous houseplant in the Oxalidaceae that looks like a tiny palm tree and is sometimes used as a tree substitute in terrariums and fairy gardens. It is modestly touch sensitive … but its leaves move all on their own much of the time, albeit quite slowly.

Finally, the partridge or sensitive pea (Chamaecrista fasciculata), a fairly common annual species of legume native to the eastern United States, also has pinnate leaves that close at night … and are slightly sensitive to the touch during the day.

Touchy Feely Carnivores

The other group that includes plants sensitive to touch are carnivorous plants or, more correctly, insectivorous plants.

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Venus flytrap (Dionaea muscipula) with its leaf traps. To learn how to grow this capricious plant, read No Hamburger for the Venus Flytrap. Source: Citron / CC-BY-SA-3.0, Wikimedia Commons

The best known of these is the Venus flytrap (Dionaea muscipula), often offered as a houseplant, although rarely very long-lived in the average home environment. I already wrote a bit about this plant in 5 Plants with Weird Foliage. It’s bear trap-shaped leaves are dotted with tiny hairs. If an insect touches one hair, nothing will happen. This is believed to be a protection to keep leaves from closing for inopportune reasons, such as when a raindrop or a fallen leaf touches it. However, if the hair is touched a second time within 20 seconds, or if a second hair is touched within the same time limit, the cause is probably a wandering arthropod and the trap closes rapidly, in one tenth of a second. After that, the insect is slowly digested, then the trap opens again. It takes 5 to 14 hours for the trap to reopen after a false alert, while actually digesting an insect can take 10 days or more.

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The trap leaves of bladderworts (Utricularia spp.) do their job underwater, so it’s not easy to see them catch their prey. Source: wetland-plants.co.uk

Less well-known than the Venus flytrap, bladderworts (Utricularia spp.) are even faster. Their bladder-shaped trap is small modified leaf, so designed that when it is “set,” a vacuum forms inside the bladder. If a water flea or other small invertebrate touches the sensitive hair on the outside, the trap opens, instantly sucks in the creature, then closes. The whole process only takes ten to fifteen thousandths of a second.

Gardeners won’t likely find this trap as fascinating as that of the Venus flytrap, as all of this action takes place more or less out of sight underwater or even underground in soggy soil, as bladderworts are bog or aquatic plants.

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Some sundews (here, Drosera capensis) have leaves that will (slowly) wrap around the insects they have caught. Source: Noah Elhardt, Wikimedia Commons

Other insectivorous plants show some leaf movement. Some sundews (Drosera spp.) have leaves that will slowly wrap around their prey once it is glued to the sticky glands that cover them, but this happens so slowly you’d need a time-lapse camera to notice. Butterworts (Pinguicula spp.) leaves also roll up slightly when they trap a prey item, but their movement is even less impressive than that of sundews.


Leaves that move: one of Mother Nature’s little surprises!20180211A www.oogazone.com & freedesignfile.com.jpg

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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: http://www.gardeningknowhow.com

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: laidbackgardener.com

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: http://www.amazon.com

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: www.orchardnursery.com

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: cdn.shopify.com

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)

 

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Butterfly Palm (Dypsis lutescens). Source: http://www.ikea.com

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

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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: thesucculentsource.com

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: pistilsnursery.com

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: http://www.planten-kopen.com

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)

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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: garden.org

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: http://www.amazon.com

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: amazon.com

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: amazon.com

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.)

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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: carlosbato-arte.blogspot.ca

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: www.homedepot.com

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: www.homedepot.com

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: www.waitrosegarden.com

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: goodtogrow.files.wordpress.com

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 www.gardeningknowhow.com