The leaves grow well in Malaysia but on and off there seems to be like rust and damage on the leaves. How can I save the plant?
It sounds like the plant is prone to rust fungus. In warmer climates where the plant is not getting good air circulation, this can be an issue. Treat the plant with a fungicide and, if you can, place it somewhere that it can get better air circulation. Basically, somewhere that the wind can move the leaves a bit.
The fungicide will kill the current fungus and better air circulation will help keep it from coming back.
I have the bulbs growing in a pot now. Can I bring the whole pot indoors over winter or am I suppose to dig up bulbs and dry? I never have any luck holding over bulbs. The leaves look really nice and I would like to save them for next year.
Yes, you can. Caladiums are popular as indoor plants, so they would do well over winter. They typically need to be watered a few times over the winter if left in the soil.
A few years back, I received a potted Caladium. I transplanted it and it took off. Then I split it into 2 plants and they've grown even more. My question is, why would the Caladium start shooting off LONG branches with healthy leaves? Does this mean it's time to split the plants further? Would the Caladium be looking for more places to put roots so it can expand?
It could be that it is overcrowded. That can cause growth like that. It may also be that it is not getting quite enough sunlight. They will stretch out like that in an attempt to get more sunlight. Dividing them certainly won't hurt, but you may want to check that they are getting enough sunlight as well.
My caladiums are doing pretty well. However, some of the trunks tend to seemingly be unsupportive of the leaves. Most of the leaves stand up proud. Is this to be expected or is there something I could be doing differently?
This typically indicates that the plant may not have enough sunlight. The stems are stretching out the leaves to find more. If you can get a bit more light to the plant, this should help.
I have just been given several hundred caladium bulbs. Should I plant them or store till sping? If I should store them, are there special directions?
Depending on your region, you may want to store them. This article will help you with storing them: http://www.hort.purdue.edu/ext/HO-085.pdf
If you live in a warm climate, however, you can plant them. This article will help: https://www.gardeningknowhow.com/ornamental/bulbs/caladium/when-to-plant-caladium-bulbs.htm
I have two of each of the above plants. I would like to "over winter" them as houseplants. Can that be done or should I cut them back to the bulbs and store the bulbs?
Yes, you can. Both caladiums and elephant ears are popular houseplants and do well as indoor plants. You just need to make sure they stay watered and that there is relatively high humidity.
I asked earilier today about planting caladiums -- I read the article, which says I can plant them on Mar 15 for my zone (9) -- my question is, can I still plant them now? Or should I store them till the spring---- storing the number of bulbs that I have at 50-55 degrees is going to be difficult.
For your zone, it will not hurt to go ahead and plant them now.