Jorge, I bought a small A. bulbifer plant 2-3 years ago. I put it in partial shade, and, lucky for me, it has been growing quite well. I believe it needs a well drained medium that retains water well, and needs to be watered regularly. I have a few A. bulbifer plants now, and I water them every 2 or 3 days so the medium stays at least moist and never dries out.
When I bought the original plant I had it growing on a rack with some orchids. After about a year I noticed another A. bulbifer growing in the ground under the plant on the rack. I couldn't understand how it reproduced because the original plant never bloomed, so it never had any seeds. I did some research and found out that A. bulbifer has what looks like a button mushroom on top of the stalk. (For those who are not familiar with the plant, it looks like a small tree that has a trunk and large spreading leaves on top of it. But technically, the whole thing is a leaf, if I remember correctly.) The thing that looks like a button mushroom is called a bulbil. After a while, the bulbil drops off, falls to the ground, and grows another plant. It turns out that the ground was a better medium than what was in the pot because the plant on the ground grew larger. A. bulbifer goes into dormancy during the winter, and the leaf dies. When that happened, I dug up the tuber that was in the pot and stored it in dry peat moss, which I read somewhere I was supposed to do. Over the course of a few months, I dampened the peat moss occasionally. A month or so ago I took the tuber out of the peat moss to look at it, and it was beginning to grow roots. I planted it and began to water it, and a new leaf shot up. So I was feeling pretty good about myself, having successfully navigated the plant through dormancy. But a few days later the tuber that was in the ground, which I left there, also grew a new leaf, which got much bigger than the one in the pot. So much for theory. The ground is just some soft soil that stays damp because it gets water from the draining orchid pots, and it's always in the shade. I figure that maybe the plant in the ground was bigger because the roots could grow out more compared to being in a pot. Unfortunately, I had to dig the plant out of the ground because it was getting too tall (3 ft., eventually) and it wouldn't be able to grow through the rack. It's now in a big pot. Though the plant has never bloomed, the leaves are quite beautiful. They have a nice shape and are green with a thin pink edging. I have had no problems with insects, slugs, or mildew/fungus/etc. The bulbils from the end of last season are now growing. Sorry this is such a long post, but I just felt compelled to tell about my A. bulbifer.
I am not familiar with A. bulbifer cultivation, but I do have a Gonotopus bovinii (or similar spelling) back in Germany. It looks relatively similar to the mentioned plant. What I observed is, that you can also tear of a piece of the leaf (that looks like a leaf itself anyway) and put it on the soil. It builds very quickly a tuber and starts growing into a new plant soon after.
There are many Amorphophalli around the southern Philippines, especially in Mindanao, some of them with spectacular stems. Another obviously salt tolerant variety I saw on a tiny deserted island (just 54 coconut trees!) near Surigao, where I got stranded with a sail boat. They all seem to like lots of water though.
Jorge, that's a great looking plant! You'll have to put it in a much larger pot next season.
Volker, I'll have to try your idea of leaf cuttings.
I'm going to try to post some photos. Apologies in advance if I don't succeed, because I'm technologically illiterate. I don't have a photo of my largest A. bulbifer, which I mentioned in a previous post, because I recently donated it to a local botanical gardens, along with tubers of two other Amorphophallus species that I won in an auction (the plants would be too big for my small yard). Anyway, here goes...
Here is a photo of a small bulbil that is just sprouting.
My A. bulbifer plants have been in dormancy for so many months that I can hardly remember what they looked like. I wondered if the tubers were still viable, as the growing medium has been constantly wet because the rain here has been of biblical proportions. In fact, it has rained every day for even more than 40 days (though not constantly). A couple of days ago I dug down to see how one of the tubers was doing. It was still hard, so it seemed to be okay. Jorge and anyone else with A. bulbifer, Is yours still in dormancy?
On the other hand, after the A. titanum seeds sprouted they have continued to grow and show no signs of dormancy.
“Real knowledge is to know the extent of one's ignorance.” “The greatest ignorance is to reject something you know nothing about” “Nothing in the world is more dangerous than a sincere ignorance and conscientious stupidity.”