The whole point of a leaf is to collect sunlight and convert it via photosynthesis into sugars for the plant’s growth. Thus, a leaf simply has to be green to be functional. You’d think a simple flat shape would be enough, but no. There are as many leaf shapes as there are plants and they come in far more colors than they legitimately should. Here are some of the more interesting and memorable ones.
Swiss Cheese Plant (Monstera deliciosa)
This is a very common houseplant whose leaves just keep getting bigger and bigger … and weirder and weirder. If you’ve ever grown one from a young plant, you know the first leaves are entire and heart-shaped (the Swiss cheese plant is often mistaken for a philodendron at this point). Then, as it grows, the leaves get larger and splits start to appear. As the leaf increases in size, the number of splits increases and then holes (leaf perforations) start to show up. The leaf keeps increasing in size and, as it does so, more and more perforations appear. If you have the space for this huge plant (they don’t call it Monstera for nothing!), the leaves can reach nearly 1 meter (3 feet across) and will be strikingly beautiful … and weird.
As for why the leaves become so “tattered” (and I use that word in the nicest possible way), that’s a matter of conjecture, but I like the theory that it’s because large leaves are like a banner strung across a street: if you don’t punch a few holes in them, the wind will tear them. I’ll write more about this phenomenon in a future blog.
The Swiss cheese plant is normally a climber and will grow best when offered a (sturdy) moss stake to cling to. It tolerates low light, but for big leaves, give it as much light as you can. This will also keep it more compact. You are allowed to cut off the numerous aerial roots it produces (I like to keep a few for show). It may even bloom for you one day, with sail-like white blooms (think of a Spathiphyllum). The fruit that follows is edible when it fully ripens and its scales start to drop off and, as the name Monstera deliciosa suggests, is sugary sweet. Other than the ripe fruit, though, the plant is poisonous.
The Swiss cheese plant is easy to grow indoors, but does appreciate good atmospheric humidity (to prevent leaf browning). Otherwise, just give it regular houseplant care … and be patient!
Cooper’s Haworthia (Haworthia cooperi)
I’m using this plant as an example of a window plant. There are many others in such genera as Haworthia, Lithops, Peperomia, Senecio, Fenestraria and Frithia, but all have the same fascinating characteristic: they have a translucent area at the leaf tip where sunlight can reach down through the gelatinous transparent leaf interior and reach the photosynthetic cells along the outside edges lower down. This is exactly the opposite to how other plants function. Their photosynthetic cells are located near the outside of the leaf, not buried deep inside.
Most of these window plants come from very arid climates and essentially live underground, with only their leaf tips exposed, each acting like a skylight, allowing even the buried leaf parts to photosynthesis. When we grow window plants in pots, however, sometimes we grow the plant with the entire leaf exposed, partly to show off the leaf … and partly to prevent rot.
Window plants are yet another subject I’ll cover in more detail in a future blog, but for the moment, here’s what you need to know about Cooper’s haworthia.
It’s a small, easy-to-grow succulent that will do well on almost any fairly sunny windowsill. It produces offsets and slowly the original rosette fills in the surface of the pot with the new growths. Just grow it like any other succulent, watering only when the soil is quite dry, and you’ll have success. It will even bloom quite readily, although the flowers aren’t very showy.
To best appreciate the transparent beauty of the leaves, you do need to place this plant carefully: at about eye level, with the sun in the background. When looked down on from above, the windows are not as noticeable.
You’ll find it, or other window haworthias, in most garden centers.
Venus Flytrap (Dionaea muscipula)
There is no denying the plant has weird leaves. Weird in appearance and weird in how they’re used. A broad, winged, often heart-shaped petiole rises from a small rosette and it carries on normal photosynthesis, while the leaf blade itself forms two lobes, each with a ring of teeth around the outside. When an insect or other arthropod triggers the mechanism by touching the small hairs in the center of the leaf, the leaves close quickly, trapping the creature, then the leaves produce gastric juices to digest it. Yes, this plant is carnivorous, or, to be more precise, insectivorous.
Like most insectivorous plants, the Venus flytrap developed its feeding habits because it normally grows in a very sterile environment, in this case, nitrogen- and phosphorous-poor bogs in North and South Carolina. It needs insect “meat” to supplement its meager diet.
Although widely sold as a houseplant, the Venus flytrap is more of a curiosity than a good indoor plant, nor will it thrive outdoors under garden conditions unless you can recreate the environment of a cold, but nearly frost-free bog (zoned 7 to 9).
In most cases, it’s best to think of this plant as a temporary one, something to be tossed when you’re finished with it.
You can keep a Venus flytrap growing for years, though, if you know what to do and are willing to bow to its whims. Read more about it in No Hamburger for the Venus Flytrap.
Mother and Daughter Croton (Codiaeum variegatum forma appendiculatum)
I suppose all crotons have weird leaves. Almost always variegated, they come in a wide range of colors (red, orange, yellow, purple, green and white), plus they change colors as they mature, so leaves from different parts of the plant may be very different colors. The leaf shape too is extremely variable, from ovate to linear and entire to deeply lobed, and often twisted or spiraled.
But the weirdest of all the crotons are those so-called called mother and daughter crotons: C. variegatum forma appendiculatum. In these, the leaf, often fairly linear, produces a narrow stalk from its tip, then a smaller leaflet, often curiously funnel-shaped, appears at the extremity. It looks like a kite on the end of a string!
I sometimes get letters from readers who think a baby plant is growing from the tip of a mother leaf. Sorry, but no dice: the croton is just not one of the plants you can grow from a leaf cutting, even less from a leaf section. You’ll need to take stem cuttings (or air layer the plant) to multiply it.
There are only a few cultivars with the appendiculatum habit, one being called just that: ‘Appendiculatum’. It has green leaves, although there is also a red form bearing the same cultivar name. The other often seen is ‘Interruptum’, with green leaves mottled yellow turning into red leaves mottled orange. Never is a very common plant. Unless you have a croton nursery in your neighborhood or can order one by mail, you’ll just have to wait until one of these curious mother and daughter crotons shows up in a garden center near you.
The croton has the reputation of being a persnickety houseplant, but I have specimens over 20 years old and they do just fine. Of course, I lost more than a few until I figured out that what they really need is high humidity until they settle in. Ideally, buy them in late spring or summer, when the air is naturally humid, and put them in their permanent spot, which needs to be a brightly lit one. By the time the dry air of fall arrives, they’ll have had time to adapt to your conditions and should do fine. Other than that, basic houseplant care is all they need … but do keep them out of cold air (less than 60˚ F/15˚ C).
Crotons also make great outdoor shrubs and even hedges, but only in truly tropical climates (zones 10 to 12).
Ginkgo (Ginkgo biloba)
Most really weird leaves are found on tropical plants, which is normal considering the vast majority of plants on this planet are of tropical origin, but there are still many leaf oddities among hardy plants and I think the ginkgo clearly merits a spot in the list of weird leaves.
Maybe you’ve seen ginkgoes around you so often they’ve come to seem quite ordinary to you, but their leaf shape is in fact unique among seed plants. Only maidenhair ferns (Adiantum spp.) have leaflets anything like them.
Each leaf has a very special fan-shaped form, caused by veins that split in two, then split in two again and again. It’s as if the needle of a pine started out narrow, then became increasingly crested from the mid-point on. And ginkgoes are indeed gymnosperms, closer relatives to conifers than to flowering plants, in spite of their broad leaves and deciduous habit.
250 million years ago, ginkgoes were the dominant trees on our planet and were apparently a major food source for dinosaurs. There is only one species left, G. biloba, rarely found in the wild and even then only in isolated areas of Southwestern China. However, it is now grown as a cultivated plant the world over in hardiness zones 4 to 9.
The ginkgo is a very slow-growing but forgiving tree, adapting to just about every condition as long as drainage is good.
More Weird Leaves to Come
I’ve only scratched the surface of plants with weird leaves. I have many others I want to present to you and hope to do so over the coming months. Also, I’m looking for suggestions. Maybe I’ll be able to include your choice in one of the future blogs! If you allow me to use one of your photos, I’ll add that too! Just write me at email@example.com.
Do note I’m looking for plants that repeatedly produce odd leaves, nor for a single mutant leaf on an otherwise normal plant, nor do leaf oddities provoked by insects or diseases count (although I have to admit some leaf galls are pretty amazing!). Also, for the moment, I’m sticking to leaves, not weird growth habits or weird flowers.
Thanks for any help you can offer!