You’ve probably seen those fascinating pictures of orchids at fairs and shows with literally uncountable Cattleyas blossoms open on a relatively tiny plant. Jaw-dropping to say the least. Cattleyas will generally produce one flower per pseudobulb if they are young plants. Once adults, they can grow two or more—mostly two—per new pseudobulb.
So how do the growers induce Cattleyas to make more flowers? It’s all in the pruning.
To prune Cattleyas, you are in essence inducing the production of new pseudobulbs. Pruning Cattleya orchids so they grow back bushier and with more flowers will involve: 1) finding the rhizome, 2) locating the active eyes, 3) making a tiny cut to sever the rhizome halfway through the orchid, and 4) sealing that cut with fungicide.
I know that was a lot to grasp at once, so let’s look at those steps one by one. If by chance you are looking for an article that talks about pruning Cattleya orchids as in cutting the roots and finding out which ones need to go and which ones need to stay, then I suggest this article I wrote. It’s more tailored to root pruning and maintaining healthy roots than pruning to produce flowers.
The objectives to each article are different, so the outcomes will be drastically different. Of course, if pruning your orchid to produce more flowers, then you are at the right place. One more note: this article only works for sympodial orchids (Cattleya, Oncidium, Dendrobium and Cymbidium) not monopodial orchids (such as Phalaenopsis and Vandas).
1) Finding Your Cattleya’s rhizome
If you haven’t read my article about Repotting Cattleya orchids, then this may be the perfect time to do so before you continue. You can read it here. In that article, I talk about the way Cattleyas supply nutrients through back bulbs to the newer bulbs, and that is important to understand now.
If you don’t want to click away then come back, I totally get it. I’ll summarize here, but please be sure to go back to that article, where I explain this is much more depth.
A Cattleya rhizome will be thicker than normal roots and travel horizontally across the length of the pot. Each orchid will have a main rhizome, and if you’ve never really messed with it, it should be the only one.
There are exceptions to every rule. One of my Cattleyas looks like it has no idea what it’s doing, dividing the rhizome in multiple places to zig-zag across the pot. Even with the unruly rhizome that bifurcates and divides into multiple rhizomes creating a spaghetti bowl of roots, you should still be able to identify the main rhizome.
There should be one central direction in which it grows. The older pseudobulbs will be to the outer rim of the pot, while the newer pseudobulbs grow along this rhizome to the middle portion of the pot.
2) Locating the Active Eyes on A Cattleya Orchid
You might be wondering why I had you find the rhizome. What’s the point? Well, there is an objective—locating the active eyes on your pseudobulbs. One the newer pseudobulbs toward the bottom near the base, you should see an expanded part. It’s almost like a little portion of the pseudobulb is swollen. This is the eye of the pseudobulb, and it’s where new pseudobulbs grow.
When these eyes are in the growing stage, they are extremely tender and break off easily. This is important to note when dealing with your orchid. You want to take extreme care to not break these off since an entire new pseudobulb will grow from these active eyes.
Start with the newest pseudobulb and work backward, locating the eyes that have already produced pseudobulbs, and ones that still will. Sometimes a pseudobulb can have two eyes and grow two new pseudobulbs that year, so look around each one 360°. Anywhere there is an active eye that hasn’t grown out yet, move back to the next, older pseudobulb.
Make a mental note of when the active eyes are already grown out and when they still haven’t. From this point backward, moving down toward the older pseudobulbs, you will induce the orchid to produce new pseudobulbs.
3) Make a Cut ½ way Through the Rhizome
This is the worst part—cutting the orchid. But it needs to be done if you want a fuller, more robust Cattleya. Pruning always involves cutting, but this time, instead of the leaves or roots, you’re going to cut the rhizome itself.
Sterilize all your equipment; wash your hands; be careful. This is vital. Leaves are tough by themselves to not let bacteria and other microorganisms into the cut portions, yet even then it’s good to use a sealing agent, for example, cinnamon.
But this is worse than that, you are pruning a vital structure of the orchid.
You’re NOT going to cut all the way through. This would be diving the orchid and that’s another article (which you can read here). The aim is to sever this connection, so it doesn’t have total access to the nutrients and water that run through the xylem and phloem that provide the orchid with nutrients.
3A) Understanding the “Why” Behind this Pruning Method
The back bulbs are on the Cattleya orchid simply to provide nutrients and water.
If they still have their leaves, they will transform the light into energy, by photosynthesizing. The more energy, the healthier the orchid. These older generation Cattleya orchids will take care of the newer pseudobulbs, making sure they receive all the care they need. Think of these older bulbs as grandparents that provide an endless amount of chocolate chip cookies to their grandchildren.
These nutrients follow an intricate network of ‘veins’, channeling nutrients throughout the orchid. When the orchid senses that the rhizome has been severed, they have nowhere to send these nutrients that they won’t use themselves. They immediately think about self-preservation (if orchids can think) and start to urgently send hormones and enzymes to the older pseudobulbs to make new active eyes.
If they don’t, they will certainly die—that’s what they assume. The truth is that the rhizome wasn’t severed all the way, so the newer pseudobulbs will receive some nutrients. They won’t be isolated and excluded from the main plant, just badly severed.
These enzymes hurriedly produce new eyes, which in the long run, will make new bulbs, and over the next year, produce a new flower. So, for each interval in-between the pseudobulbs, you can make a slit halfway through the orchid, and it will develop a new eye.
Don’t get carried away though. This method involves a harsh growing-up regime, and sometimes the orchid just isn’t ready for it. Even though you technically can cut in every free space in between pseudobulbs on the Cattleya rhizome, I find that’s harsh. I’d cut two or three and leave the rest alone. If the orchid reacts well to this, next year during the same time, cut the places that you didn’t cut this year.
Intervals—it works wonders.
The instrument that you use needs to be extremely sharp and efficient (and sterile). Here is where my mind fails me, but I like those little saws that are handheld and you can carry in your purse (not sure why I’d need it in my purse, but anyway…). With a tiny, teethed blade, you can saw your way through—but just halfway. Do NOT cut through the rhizome. I can’t emphasize this enough.
3B) Methods that Don’t Work in Pruning Cattleyas
You might think that this is harsh. You’re right—it is. There have been several other methods that have worked in the past, but each one has its downside. I found cutting the Cattleya rhizome in the way that I explain, gave better results in the long run.
I’ve seen some people come with a clamp, or metal cutter and squeeze the rhizome until it’s pretty messed up. I don’t like this because it’s hard to apply fungicide to all the open and damaged cells that are leftover. With one straight cut you can cleanly apply the fungicide, sealing the wound with cinnamon.
Other orchid growers have used pins or nails, making one huge hole in the rhizome (or tens of smaller holes). This also is drastic because nails rust, and even if you take it out, the rhizome is still intact for the most part. The orchid doesn’t sense the fear and danger; it thinks some big bug took a chunk out of it.
No harm done.
The best way is to make the surgically clean slit in the rhizome and keep it spotless, clean, and functional.
4) Sealing the Cuts with Fungicide
Now that the cuts are strategically placed around the orchid, you need to seal them off, so no microorganisms find a new home. You can use fungicide, bactericide, cinnamon, all three, but hydrogen peroxide really doesn’t do the trick here.
Hydrogen peroxide will tickle the bacteria, not kill them. You can read more in this article about why I’m not so fond of Hydrogen peroxide.
In any case, seal the wounds several times by spraying with any type of killing agent that you have. Remember, this must be done thoroughly, much more than a cut leaf or a root. This is the rhizome were talking about, and when microorganisms can enter here, they have free access to the entire orchid from within.
Once the rhizome gets infected, there isn’t much you can do. The microbes have all they’ve ever wanted.
And you are all set!
Your orchid will start to grow new pseudobulbs and from there, new flower spikes. In time, these will bloom all at the same time. Oh—that reminds me of one more point. If you are cutting the rhizome, make all the cuts at the same time of year, so the blooms will grow at the same time.
Unless you want an orchid that is going to be blooming all year round in different months, (which is beside the point of this article, to make a fuller, more numerous blossoming orchid) then make sure you are cutting the rhizome at the same time. Whatever time of year you decide to do this method, avoid the flowering stage. It’s too much for your orchid.
Another point to ponder—this will not work if your Cattleya isn’t getting enough light, water, or fertilizer. No matter how many cuts in the rhizome you make, if your Cattleya is sick it won’t matter. It’s already struggling to maintain what it already has in bloom. There is no way it can handle any more. In this case, you need to verify that your Cattleya is doing well and has sufficient light.
To go over a checklist and see what your Cattleya needs, you might be interested in this article I wrote. It’s 7 things you need to verify so that your Cattleya is in tip-top shape to bloom. Once those items are covered, then you are covered.
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