Succulent, the most “suc”-cessful survivor that can be found in arid areas such as desert when nothing is found. Then how about cactus, the most famous desert plant? Well, succulent commonly named as xerophytes, xeros means dry, because of their adaptability to live in a dry environment. Cactus (plural cacti) is one of the widely known examples of succulents. Almost all cacti are stem succulents. Overall, succulents are briefly referring to the rosette-plants that have thick and fleshy leaves.
The mighty Nature has managed to allow the plants to undergo adaptation to suit a wide range of unusual environments from ponds to deserts. In dry areas, plants adapt to survive with only a small amount of water at irregular times. Morphologically, they have reduced leaves such as spines which are the modified leaves that have sharp-pointed or needle-like shapes. Whereas, thorn technically is a modified stem that has a sharp-pointed stem that can be found on citrus trees and roses.
The fleshy organs consist of water-storing spongy tissues which help to store a large amount of water. Some succulents have developed other specialized characteristics such as secretive underground organs like bulbs, corms, and tubers that often fleshy as well. Their leaves grow a thick and waxy layer called a cuticle layer that acts as a barrier to protect the inner soft tissue. It also helps to reduce the heat through the reflection of the light via the waxy cuticle layer. And the reduced number of stomata helps in reducing the loss of water through transpiration.
Succulent plants are on the night shift to take in carbon dioxide when there is no sunlight. This is uncommon as they store up carbon dioxide for the photosynthesis that carries out the next day. The main reason is to protect themselves from water loss by remaining the stomata closed in the daytime, which is scientifically known as the crassulacean acid metabolism (CAM) pathway. Cactus can be classified into a rainforest, prickly pear, columnar, and globular cacti. Some succulents plants that can be found in arid areas such as agave, baobab, boojum tree, cactus, epiphyllum, yucca, dasylirion. The more familiar ones in the nursery for ornamental purposes such as dudleya, sempervivum, crassula, kalanchoes, graptopetalum, cotyledon, echeveria, aloe, and sedum. There are also epiphytic succulents that cling on rocks or trees and absorb the moisture from the air. And succulents with distinctive features such as Haworthia, known as window plants that have transparent tips and lithops that look like stones.
As slow-growing plants, some species always look compact, columnar, or spherical with shallow roots. Succulents have been one of the most popular desk plants due to their small size, variation patterns, colors, and forms, especially their low maintenance feature that makes them the most popular desk plants. Especially for lazy people who only look at their plants once in a while, neglect is the excellent practice in taking care of succulents as they are growing better under drought conditions. They are still there whenever you take a long vacation. They are often “killed” by intensive care such as misting or watering every day. If succulents are located near to the open windows, there is no need to water them if there is rain occasionally. They are capable of absorbing the moisture through the ventilated air. Besides, they like warm temperatures, bright and direct sunlight as well.
It is highly recommended to frequently propagate the succulents to avoid the ignorance of pests such as mealybugs that often attack and accumulate at rosette part of the stems thus causing wilting. Propagation is easy through leaf pulling and stem cutting. Leaf pulling is the most favored method as it induces somatic embryogenesis naturally. By merely lying the leaves on top of the soil, with or without misting after two or three days, will eventually induce plantlet formation at the wounded side of the leaves. Sometimes, there will be clumps of newly formed succulents that can be sold at a higher price due to their unusual form. Furthermore, somatic embryogenesis has the potential to give variegation which is highly favored by hobbyists and collectors. Variegation is the mutation at the epigenetic level in which the genetic sequence of the offspring will still be the same as the mother plant but morphologically differed from the mother plant in terms of colors. The strips of white or yellow colors of a succulent could be sold at a price doubled or tripled than the original plant. However, the variegation sometimes might not be permanent and can be induced under certain conditions such as abiotic stresses like reduced watering over months and the ratio of fertilizers supplied.
Succulents can be germinated through seeds, but the flowering stage drains the energy from the mother plant. Stem cuttings in succulents is a win-win situation in which it eliminates the risk of pest at crowded leaves and produces multiple succulents babies. The cut stem can be directly planted into the soil as a new individual. The remaining part remains as a mother plant to induce multiple baby plants by lateral dominance, a term used to describe lateral bud formation when the apical part is removed. Avoid watering within a week or planting the cut in wet soil. Succulents have water-storing tissues and very sensitive to watering if it gets wounded. Too much water will cause bacteria infections on the wounding sites that leads to rotting. If rotting observed, the damaged tissue must be cut immediately to stop the spread of bacterial infection to other plant parts before it is too late.
There are trending practices that are popular on social media that grow stem cutting in water. They maybe look elegant and special due to the fibrous roots that occur. However, it is not healthy for long term growth. Due to the lack of nutrients in the water, they would not look healthy and get etiolated quickly. Succulents are very demanding for aeration in soil and drainage of the water. The soil must consist of the substrate like perlites which increase the pores in the soil to allow their roots to breathe and fast water drainage. it’s critical because, in nature, succulents thrive in the desert with little water, they do not like watery wet places. They absorb water through morning dew or the moistures from the air, and for cacti, the spines help the moisture to condensate and perform “self-watering” in nature. The tip is to water them only if the soil surface and soil are entirely dried until almost cracked while ensuring the water is drained thoroughly.
Before buying succulents from free markets, it is always suggested to ask for the scientific or common name and search for its original colors and variegation forms. It has been reported that some sellers would paint or spray the succulent with dyes to make them look bright and colorful. In many cases, those artificial-colored succulents would die within one to two weeks. The coating of the paints covering part of the or whole leaves and blocking the stomata to absorb CO2 and water from the air. Knowing the correct scientific name of the plants also helps to find out the most favored growth conditions and horticultural practices.
Besides as an ornamental plant, some succulents also can be consumed! The most common edible succulents are aloe vera, dragon fruits, fruits of saguaro, opuntia, and barrel cactus. Many of them also can be further processed into downstream products such as aloe vera gel in the cosmetic industry.
Further readings:
Broogh, H. (1982). The Illustrated Encyclopedia of Cacti and Other Succulents.
Sajeva, M., & Costanzo, M. (2000). Succulents II: the new illustrated dictionary. timber Press.
