With our persistent drought, and the possibility that it signals a long-term change in our climate, gardeners are becoming interested in succulent plants. They warrant a closer look.
All plants store moisture in various parts of their anatomy. Succulent plants store more moisture than plants in general, having adapted to surviving in areas of irregular rainfall.
Succulence is a characteristic of plants, rather than a taxonomic category. As a result, identifying succulent plants can be an arbitrary exercise. For example, some gardeners will group succulents apart from geophytes and cacti, although both store moisture. That’s OK, because “succulent” is not a formal definition, but it’s still appropriate to think of geophytes and cacti as good at storing moisture.
Succulents are found in about sixty plant families, and a wide range of genera within those families.
One unusual group of succulent plant is the caudiciforms, which store moisture in a caudex, which is a woody stem structure that typically develops just under the surface of the soil. Gardeners who enjoy growing these caudiciforms in containers often adjust them to display the caudex above (or partially above) the soil surface. The caudex, also called a “lignotuber,” is not attractive in the conventional sense, but by any name it is an ingenious adaptation of the plant to unreliable moisture conditions.
My garden includes two caudiciform plants. One is a Ponytail Palm (Beaucarnea recurvate), from Mexico, which is not really a palm. The cultivation advice for this plant is to never water. This might seem harsh, especially for gardeners who equate watering regularly with nurturing the plant, but it indicates that the plant is epiphytic, meaning that it derives moisture and nutrients from the air, rain, and sometimes from debris that accumulates around it.
Ponytail Palm (Beaucarnea recurvate). Click to enlarge the photo, and make more visible the caudex at the base of the plant.
My other caudiciform plant is a Beautiful Serpent (Agapetes serpens), which is from the Himalayan mountain range north of India. It is in the Ericaceae (Heath) family. The plant’s specific name refers to the snaky growth of its stems, but its blossoms are more distinctive, in my view.
I have not seen the common name, Beautiful Serpent, online, but that’s what I call this plant.
Both photos of Agapetes serpens are from Strange Wonderful Things: Rare and Exotic Plants which is a fine website for gardeners to visit.
I found this rather rare (or at least uncommon) plant in a local garden center, then found online cultivation advice that emphasized bright but cool conditions, with protection from the afternoon sun. This seemed appropriate for a plant from the Himalayas, so I put in a container of about 1.5-gallon size, filled with good potting soil, placed the pot in a bright shade location, and watered it regularly.
The plant grew well enough, but has produced few stems and blossoms, compared to photos I have seen online. It didn’t seem happy.
With a bit more research, I learned for the first time that this plant is a caudiciform. The caudex is below soil level, so this was a surprise. Then with further research, I learned that it is also epiphytic! This is a game-changer.
Not all caudiciform plants are epiphytic, but they use available moisture very efficiently, so irrigation should at least be limited.
My cultivation plan for this plant now involves keeping it in the same bright shade location, and discontinuing irrigation. Reportedly, it prefers humid conditions, so I might mist it occasionally.
The first takeaway from my experience with this plant is to find more than one source of information on unusual plants that you bring to your garden. The Internet holds an amazing wealth of information of value to gardeners, and we should draw upon it routinely.
An important first step in researching a plant is to learn its botanical name. A search based on a common name often will lead to good information, but the botanical name is more accurate and preferable.
Try one or more caudiciform plants among the succulents in your garden. A rich source of information on these plants is the website bihrmann.com. Hint: when you browse to the home page, click on the image immediately after “.com.”
Incidentally, you might enjoy exploring this website, which has many images of flora and fauna, in several categories. The author, identified only as Bihrmann, has travelled extensively, taken an enormous number of photographs and lived a rich life. Some of the pages are in Danish.