Here’s how it goes: Want some spiky things? Make up a list and head into nursery. See something called Cactus? Check! You got a vine that trails, a tall one, and a round one.
You’re such an expert; succulents are hardy plants who will forgive you if you forget to water them. But once you get them home…you water them all the same. Oops. Half die… Brown mush. Why?
How to Care for Different Cacti
It was not because you were doing anything wrong with the care routine, but because you assumed that all these look-alikes requires the exact same routine. Many of us tend to treat the whole family as a kind of single unit.
To get a better sense of all this, botanists divides the family into four subfamilies, which branched off in separate ways but are still kind of cousins (evolutionary speak). As the chart shows, each branch can be further defined by characteristics such as spine-ness or leaf-lessness.
For instance, most of us think that cacti lack leaves. But one of those subfamilies, Pereskioideae, does: It’s basically got an ancestral shrubby version of itself, with actual leaves, and not your typical image of desert sculpture at all. This tells you they didn’t shed their greenery all along. They evolved it away.
Common prickly pears belong to the Opuntioideae grouping. Here, the giveaway is visual: They have glochids, which are small, painful spiny barbs that embed in your fingernails. When you’re looking at a jointed or pad cactus, watch out. You need to be gentle because it’s telling you to beware through touch. It is a cautionary sign for sure.
Most cacti is in the Cactoideae subfamily, including barrel cacti and those tall, skinny ones (columnar giants). It’s just one family but it includes most of all the cacti we know. And they’re broken up into tribes based off their growth habit.
Want a cactus that looks like a vine? There’s a tribe for that, epiphytic vines clinging to a canopy of trees in a forest. How about a tree-like giant that soaks up all the desert sunlight? That’s another tribe. Or maybe you want a window-sill cactus (globe-shaped? Yep). Tribe tells you whether a plant expects baking desert sun or dappled forest shade.
People make mistake of thinking you can judge a cactus just from its form. Remember: Cacti can evolves similar traits independently, so a round South American cactus could be the same as a round North American cactus. But it’s not; they’re in different tribes and have different water requirements.
The classification system calls your attention to those secret differences. “Look beyond the silhouette,” it says. “Examine the areoles; the little cushions that spines grows out of.” That areole structure is the cactus fingerprint. That structure doesn’t appear on any other succulent.
Plant labeling can be more than simply a class, it’s a form of biology. Treating a dry-habitat columnar cactus like a jungle cactus invites rot. Knowing its classification help you know what to expect. Night-blooming cereus types are climbers, for example. Barrel cacti has evolved to store water slowly.
When you pick up that spiky friend, look at its areoles (those spots where the spines arise). Any left-over bits of leaves? Any little barbs? Is it a plant of a humid understory, or did it evolve in a dry canyon? Where’s it from?
The answer is to read the label on what you shop with. It’s usually just a name. The way it is put together is the story. You should of read more closely.
Over-love it, and you may kill it. Know when to back off.