Neglect. The ability to withstand extreme neglect. It’s the defining characteristic shared by those houseplants known as “succulents.” From the fleshy leaves of the “Jade” and “Aloe,”
to the spiny leaves of the cactus, to the sporadically leafless “Crown of Thorns,” succulents are able to survive droughty conditions that would quickly do in a geranium.
Native to hot, dry and otherwise inhospitable parts of the world, succulents, like camels, are able to store water in leaves, stems and roots, making them independent of the neglectful care of indoor gardeners, like The Opinionated Gardener. But be forewarned; just because they tolerate dryness, they do not tolerate overwatering.
It is the succulent’s peculiar, often bizarre shape, however, not its ability to withstand neglect, which appeals to the OG. No other group of plants ranges as widely and wildly in form and texture as the succulents. But then again, succulents comprise no less than 30 different plant families – there is no one family known as “Succulentaceae.”
When sitting solo on a winter window sill, on a shelf against a white wall, or, as a last resort, on the floor, succulents become an object of art, a piece of minimalist and modern sculpture, if you will.
The OG’s sense of aesthetics aside, at the heart of the matter is the fact that what gives them their often “peculiar” shapes are the very adaptations that have enabled them survive times of drought in deserts. Or more recently in times of neglect in wood-heated houses; as the garden writer Tovah Martin (see sidebar) in her history of indoor window plants reminds us “it was only in the last (18th) century that plants began to move indoors.”
Three succulents to know and neglectfully care for:
While there has always been the succulent, commonly referred to as the “Burn Plant” aka Aloe vera in the OG’s kitchen, it wasn’t until she acquired a “Propeller Plant” from Camden’s Merry Gardens that her fascination-obsession, with succulents began. In the 20 years since, many succulents have found their way onto her window sills – at last count there were 15 different species – and when the window sills groaned under their weight, they were then placed onto floors and the tops of bookcases. The OG counts the following among her favorites:
Native to the Eastern Cape in South Africa, as are most of the world’s succulents, the “Propeller Plant,” like its cousin “Jade,” stores water in its leaves. In botanical circles, it goes by the name Crassula falcata because its thick (L. crassus), long gray-green leaves are shaped like swords or sickles (L. falcate). While the fleshy leaves are not coated with wax to keep water from evaporating as they are in the “Jade” plant, the leaves of the “Propeller” are covered with millions of scales that give it the gray of the gray-green look and that are designed to trap moisture. The leaves are also slightly concave and for the most part vertically arranged, reducing surface exposure to sun and therefore water loss.
And like many other succulents, Crassula falcata not only stores water, it also conserves water. It does this by a unique form of photosynthesis called CAM or “Crassulacean Acid Metabolism.”
(The OG may be going too far, but for those who are curious, check the sidebar). So don’t worry if you forget to water, you always have CAM to back you up.
Pencil Plant a.k.a. Milk Bush
Also native to South Africa is the “Pencil Plant.”
It arrived at the OG’s as a modest twiggy houseplant some 20 years ago; it is now a sprawling shrub propped against walls, bookcases, and couches and measures a floundering five feet in length. While not everyone would consider it aesthetically appealing, it is definitely a conversation starter. Its leaves are miniscule and few, found only at the tips of the fleshy branches a few days after it has been watered, only to disappear a few days after they have appeared. Its common name comes from its water-storing, pencil-thick stems.
The toxic white milky sap that oozes from a broken branch gives it its other common name -“Milk Bush” – and identifies it as a member of the family Euphorbiaceae along with the “Poinsettia,” which is not a succulent, and the “Crown of Thorns,” which is a semi-succulent. “Crown of Thorns,” like the “Pencil Plant,” readily drops its leaves when the soil becomes dry for the leaves do not serve to store water as they do in the “Propeller Plant.”
Euphorbia tirucalli. That’s its botanical name. For those obsessed, like the OG, with scientific names, Euphorbia comes from Euphorbus, the first century physician to King Juba of Mauritania, who used plants of this genus as medicine. When it comes to the species name tirucalli, the best the OG can determine, thanks to the folks at the South African Biodiversity Institute, is that it is the name used by the natives of Malabar a region in southern India, where it grows to tree height!
It’s not the long, thin and drooping strap-like leaves, it’s the strange swollen, bark-covered, water-storing, bulbous base that puts this plant in the succulent camp. As long as the base is full bodied, there is no need to water this plant, which is native to Mexico. The OG waters her 3-foot-tall, 10-year-old once a month at most in winter and rarely the rest of the year. But then again it is not in direct full sunlight on the top of a bookcase, as the drooping leaves are too long to set the plant on the window sill.
Don’t worry if the fire in the woodstove goes out, this plant is said to tolerate temperatures down to at least 20 degrees Fahrenheit. And don’t let the name fool you, even if its trunk looks like a palm, it isn’t. On the subject of names, near as the OG can tell, botanists haven’t yet figured out where this plant belongs in the scheme of classified things. While some place it in the Lily family, the OG favors those that places it in the family Agave, which also includes the yucca plant. Its botanical name is Nolina recurvata; taking its genus name from C.P. Nolin, an 18th century French agricultural writer. Outdoors, it can grow to 10 feet.
Botany 102: Crassulacean Acid Metabolism aka CAM
Crassulas have a special way of reducing water loss from their leaves without limiting their ability to photosynthesize. It’s known as Crassulacean Acid Metabolism or CAM. All plants need CO 2 (carbon dioxide) for photosynthesis. Most plants take in CO 2 during daylight hours through their stomata (pores in the leaves) and can’t avoid losing water at the same time through these open pores.
In Crassula the stomata are closed during the day but open at night when the CO 2 taken in is stored in the form of organic crassulacean acids. During the day, these acids are broken down and the CO 2 released is reused in the photosynthetic process. In this way they lose much less water yet can photosynthesize normally during the daylight hours.
Furthermore, during extremely dry periods they won’t even open their stomata at night, and will recycle the CO 2 within the cells. They won’t be able to grow at all but the cells will be kept healthy – this is known as CAM-idling. That’s why desert plants grow so slowly. (Thanks to Christien Malan and Alice Notten of the Kirstenbosch National Botanical Garden in South Africa for this explanation.)
Editor’s Note: This story first appeared in the February 2007 Daily Bulldog print issue.