Caladium hybridizing - Making your own unique plant creationBy LariAnn Garner (LariAnn)
March 19, 2008
Leaves of Many Colors
As an aroid fancier, I've had Caladiums growing from time to time throughout my gardening career. Each year I've looked at the offerings and, somehow, the color forms available seemed very similar from year to year. Listings of similar looking hybrids are often distinguished not by color, but by resistance to diseases, prolific corm-forming ability, or other characteristics that aren't necessarily reflected in visual impact. Seeing these plants year after year could lead one to believe that the "best" hybrids have already been produced and that we shouldn't expect anything really new to appear. Or should we?
As an aroid hybridizer specializing in Alocasia and Philodendron, primarily, I was inclined to find out if I could hybridize some of my favorite Caladiums and see if I could come up with something truly unique. My goal was simply to see if I could develop something I had never seen on the market, not to come up with the "next big thing". I found that I could, and furthermore, you can, too! There is no feeling like growing a plant that you had a hand in creating. Doing this is like painting a work of art using a palette of genes instead of pigments. One result of this artistic endeavor is the plants you see in the thumbnail image at right. These exist only at my place. They are some of my hybrid Caladiums and they were not bought at a nursery or big box store. I grew them from tiny seeds that resulted from my homegrown hybridizing.work.
There's more than meets the store bench
Once I had decided to try my hand at Caladium hybridizing, my first step was to see if I could find out how it should be done. You see, although I have years of experience with Alocasia and Philodendron, I know that those two are markedly different in regards to the technique required to obtain viable seed in crosses. So I had every reason to believe that the same would be true of Caladium. I was right, and the first thing I learned is that if you wait until the inflorescence is open to start your work, you are too late!
But I'm getting ahead of myself. My real first step was choosing a species Caladium as one of my parent plants. I decided on this because Caladiums have been hybridized for so many years that bringing in a fresh infusion of species genes seemed a good way to start. I had some of the Caladium that has a basic green leaf with little white and red spots. Very simple, no big splashes of red or white, or colored veins, just little white and red spots on a green leaf! Using this inauspicious starting point, I picked out several nice commercially available hybrids that I thought would yield some interesting progeny. Of course, you can use whichever two varieties you have available just to get your practice in. Once you've had the pleasure of producing hybrid Caladium seeds, you can be more particular in choosing varieties or species to try out.
My previous experience in hybridizing aroids revealed to me that when a cross works well, you can end up with a great number of plants, not all of which are ones you will choose to continue growing or working with. I am confident that this is what the commercial Caladium hybridizers have experienced as well. Who knows how many interesting plants didn't make the cut because they lacked some characteristic that the hybridizer was after? These new plants are the ones that never made it to the box store bench. Not so with your own hybrids; you'll get to choose the ones YOU want, not the ones THEY choose for you!
They plump when they're ready to cook!
So, if the opening of the inflorescence means you are too late to do the work, when do you do it? The answer is that you must cut away an opening (carefully!) in the lower part of the spathe a day or two before the inflorescence opens, and you must have some fresh pollen available to slather onto the pistils within at that time. This is one reason to have a good selection of Caladiums in bloom and with blooms coming on. This way you increase your chances of having fresh pollen on the same morning as your chosen inflorescence is ready. How do you know when your inflorescence is ready to receive pollen? That's where your intuition and sharp observational skills come in. The way I describe what I've learned is to say that a few days before it opens, the inflorescence "plumps" slightly and changes in color to a lighter shade of green (or a lighter version of whatever color the unopened inflorescence happens to be). Part of the fun is learning exactly when the time is right. You do get a day or two of grace, as I discovered that if you are a day early, you may still get seeds. The one time you will definitely face failure is if the inflorescence actually opens before you can do the deed. You can see three inflorescences in the image at right; one with some pollen near the spadix tip, one already shriveled, and the smallest one still immature. None of these is ready to receive pollen, but you could collect the pollen from the largest one in a little vial and save it for a day or two in the refrigerator if you have another bloom almost ready to open.
You will know that it worked for you within a week or so, as inspection of the pistils will reveal noticeable swelling if the cross worked. That's when your excitement is going to start because you will know you've got something cooking.
Awash in tiny seeds
Let's assume you had bountiful success and now you see swollen pistils, pregnant with possibilities. What next? The first thing I suggest is that you get some old women's stockings or panty hose and make yourself little sacs by cutting the foot ends off. You'll need to bag up the developing berries with these because to my chagrin, I discovered that when the berries ripen, the whole cluster falls apart and drops to the ground. Furthermore, ants seem to like the berries and they will carry away your new creation before you even realize that you have ripe berries! The little stocking sacs will keep the ants out and keep the berries from being lost. While your berries are swelling, you need to check them every day. Ripe berries are white and they ripen like the rise of dawn. Before you know it, they're done and dried up, if you don't check every day!
The seeds within the berries are very tiny and patience is called for in squeezing them out of the berries and planting them. If possible, use dark colored paper towels to squeeze the berries on, plus a magnifying glass and tweezers to pick out the seeds with. I put the freshly cleaned seeds into a little cup with distilled water overnight, then sprinkle them onto moistened planting media the next day. It's tedious work, but you won't regret it when you see amazingly diminutive Caladium seedlings sprouting from those tiny seeds. You should have your planting containers ready to receive the seeds. I recommend using the clear plastic containers you sometimes get take-out food in, but make sure you punch holes in the bottoms for drainage and use a fine grade of planting media. These serve well as community pots. Oh, and don't forget to label your community planter with the parentage and date of your cross. If you get something exceptional out of it, you might want to duplicate the cross at a later date.
When do I see colors?
As your seeds germinate, all the little seedlings well start out green with cute little round heart-shaped leaves. You don't see much in the way of colors until they've grown for 6 months to a year after they germinate. It may be two years before they are large enough to show their unique distinguishing colors. You'll have that long to figure out how you are going to grow out the hundreds (yes, hundreds!) of little Caladium plants you will produce. Be ready for more success than you can imagine. When I did this the first time, I pollinated a couple of inflorescences only, just to get the hang of it. If you do a lot of them, you could have your hands really full! In any event, share pictures of your new creations with your friends at Dave's Garden so we can celebrate your achievement with you. Perhaps at that time you'll decide it's time for a Caladium Roundup!
Picture Credit: LariAnn Garner, Aroidia Research