(one of) The real jade plant(s)

Species name: Crassula ovata (formerly Crassula argentea)

Common name: jade plant

Location: UWO Greenhouse

This plant is a wonderful example of taxonomy and taxonomic rules. A few days ago I profiled the trumpet jade, which is a variety of the jade plant selected for its morphologically messed-up leaves (you can read all about it HERE). It is native to South Africa, and has (to my knowledge) never been evaluated for its species status. It is likely very secure (meaning there are many individuals left in the wild that readily reproduce), but since I've never been to South Africa I'm definitely not one to comment first-hand.

Historically, the jade plant was divided into two different species based on flowers; the pink-flowered plants were placed in Crassula ovata and the white-flowered plants belonged in Crassula argentea. There is also a correlation between colours of flowers and the general shape of the leaves; the leaves of the pink-flowered plants often have longer and more oval leaves, while the white-flowered plants have shorter, slightly rounder leaves. Unfortunately, this was just smoke and mirrors and a great example of how plants confuse botanists. The "rules" that were made up for how to tell C. ovata from C. argentea were 100% artificial, and it turns out they're both the same species. The colour of the flower is controlled by a single gene and there can be gene copies for white flowers or pink flowers. Depending on whether the plant has white genes or pink genes, the flowers can be more white, more pink, or somewhere in between. Leaf shape is probably more controlled by level of maturation and environmental conditions than anything else; leaves produced in very dry conditions and high amounts of sunlight will be smaller and more ovate than ones produced when lots of water is available and the temperature is cooler.

So once a species has two names, what do we do? In the naming of any kind of biological organism, there is a rule called the "Rule of Priority". Whatever name was validly published and applied to the organism first is the name that stays. There are some ways to make exceptions to this rule (especially in animals...zoologists are terrible with following rules of taxonomy!), but I won't get into that. If I don't get to bend the rules with my thesis when I'm naming species, no one else should :)

This jade plant has been masterfully cared for. How do I know this? Look at all the flowers! I've seen the odd flower or inflorescence group on a jade plant before, but nothing like this. One thing that you often have to be careful of when it comes to flowering plants (and some non-flowering plants that are gymnosperms) is that when they "moult" because their health is suffering, it's often mistaken for a sign of great health and prosperity. Some trees are known to do this: the tree somehow knows that it is infected with some kind of disease (insect, fungal, bacterial or viral), produces significantly more seeds than it would under normal conditions, then dies pretty quickly after the big seed flush. Oak trees also do this on an incredibly predictable cycle, which is off-set with population booms of squirrels. When the squirrel population is high, the oak trees need to produce an over-abundance of acorns just to keep up. They moult and over-produce acorns in an effort to overwhelm the squirrels and hopefully reproduce instead of being completely eaten. The results of this effort can sound like it's literally raining acorns. This effort seems to be incredibly successful, since most species of oak aren't at risk of becoming endangered due to squirrel predation any time soon. The moulting of oak trees depends on the species; red oaks are on a 4-5 year cycle and white oaks a 5-7 year cycle. Is this jade plant at risk of keeling over after this flush of flowers? I'm guessing not, but I'm really not sure. If it's mysteriously absent from the greenhouse in 8-12 months, then I think I know why! If it's still there, then its just a well-loved jade plant.

Dr. Seuss' jade plant

Species name: Crassula ovata "Monstruosa"

Common name: trumpet jade, Gollum's fingers

Location: UWO Greenhouse

The jade plant, and many of its closest relatives like this one, is native to South Africa. This specific cultivar, originally thought to be a hybrid of two different species but now known to just be selective breeding with the "true" jade plant, is rumoured on gardening websites to be incredibly rare, yet everyone seems to have one. I personally had never seen this plant until I photographed it in the greenhouse, so there might be something to this "rare-ness." I even had to call it the "Dr. Seuss Jade Plant" in my notes since I had never seen anything like it! Now that I know I can master the art of growing a regular jade plant, I'm thinking of asking the director of the greenhouses to make me a cutting so I can have one of these, too. The fun you can have with succulents! The status of the jade plant and its closest relatives is unknown in South Africa. I can't imagine it's in danger of over-hunting by greenhouses and gardening shops since it is so easily propagated, but it would have its own set of natural threats like infringing on its native growth range by urban expansion and conversion of arid locations into agricultural land. Is anyone from South Africa and can comment on how common it is in the wild? Or has ever been to South Africa and has noticed it growing there?

The jade plant is one of the most common indoor potted plants (both the bonsai version and the regular "full grown" version) because of their ease of growth indoors. When I was in high school and someone told me this, I would have called them a liar since I managed to kill mine in a few short months. Turns out I killed it with kindness (this was before I recognized that plants with thick, glossy, fleshy leaves are probably succulents and so dislike being watered more often than once every couple of weeks). Jade plants thrive under conditions of neglect, perfect for those of you with black thumbs that want to try growing plants again. The same cannot be said about getting jade plants to flower; they are notoriously difficult flower-ers in pots indoors. The key is to deprive them of water in October, expose them to cool (but not cold) nights, and no more than 8 hours of daylight for October, November and December. Resume regular care in January, and by February or March the plants will be ready to flower. This sounds like a whole lot of work to me for some puny little white or slightly pink flowers; plus, the leaves are so attractive on their own!

Along with over-watering, there are a few indoor pests that are more than happy to attack your jade plants should they find their way into your home. The first are mealy bugs. They're easily removed with a toothbrush (don't press too hard! You want to scrape them off the cuticle or the waxy coating of the leaf, not scrape into the cuticle and damage the epidermis; this will lead to far more problems later on), and then the whole plant can be sprayed with a very mild dish soap solution in a spray-bottle. Make sure you cover the soil with a towel because even a slight amount of soap in the soil can damage the roots and hence the whole plant. The second problem are spider mites which can spin a white, silky web-like substance on branching points or at the base of leaves, and then at those spots the plant literally falls apart (entire branches will fall off with no prior warning, like they've been severed off from the inside outwards). The same treatment applies; take a q-tip dipped in rubbing alcohol and remove any white silk you find and spray the plant with a very mild dish soap solution, making sure you don't get too much of it on the soil.

I've heard a few people say that they use their jade plant as an aloe substitute, especially when the plant is mature and has a lot of leaves to spare. I can't imagine this working at all in their favour; there are no reports of jade plants being at all successful in promoting skin wound healing or relieving the pain of burned skin. Something tells me the placebo effect is hard at work here!