I read your advice on caring for overgrown jade plants. It was very helpful but missing one detail that I hope you can help with. My problem is that two of my older plants have grown into hanging plants. They are tall but almost like a weeping willow tree's branches, growing up and hanging down--long and lovely but very difficult to trim and control. I'd love to take the clippings and repot them, making lovely new plants. However, what can be done with the hanging branches? Also, they have grown too large for the largest pots reasonable and require two people to move them, yet I see they are now in need of larger pots. I am at a loss as to what to do with them.
For the weeping branches, you can prune them back and they will start to grow new stems from the old, which will make the plant more bushy and upright.
In terms of the size and repotting, it sounds like your plants need to be divided. Take the plant out of the pot and with a sharp, clean, large knife, cut the rootball apart into sections you find manageable and then repot them. Just make sure that a stem above has some roots below to sustain it. I know it sounds a bit brutal, but really the plants recover quickly.
Why are the leaves falling off my jade plant? Is it dying? There are also dark spots on some of the remaining leaves.
It sounds like the plant is over watered and may possibly have root rot. Cut back on watering. Water only when the soil is dry 1 inch on top. This article will help you determine if the plant has root rot:
https://www.gardeningknowhow.com/plant-problems/disease/treating-root-rot-gardening-tips-for-housplants.htm
I have a glass cylinder that I wish to plant Jade into. I have heard that you can easily put a Jade plant (green) within the rocks without soil and fill with water. Is this possible? Will my plants survive? If not, how do I accomplish this using soil without seeing soil only rocks?
You can grow cuttings in rocks and water. But, just for future reference, once the cuttings grow in water, they will no longer be able to grow in soil.
My jade plant falls over. I have it staked, but what do I need to do to correct the problem? This has been happening for about two months.
It may be getting too little light and is getting leggy. I would prune it and then move it to somewhere that gets more light. Here are some articles that will help you:
https://www.gardeningknowhow.com/houseplants/jade-plant/pruning-jade-plants.htm
https://www.gardeningknowhow.com/houseplants/jade-plant/jade-plant-care.htm
I had a healthy jade plant for several years. I did some rooting successfully, but all of a sudden the leaves started to droop down instead of stretching out. What happened?
This is typically a sign of either overwatering or root rot. This article will help you check for that and treat it:
https://www.gardeningknowhow.com/plant-problems/disease/treating-root-rot-gardening-tips-for-housplants.htm
Is it possible to propagate a piece of jade plant that accidently broke of the main plant?
Yes. This article will help: https://www.gardeningknowhow.com/houseplants/jade-plant/propagating-jade-plants.htm
What is the botanical name of the jade plant?
I believe what you're looking for is Crassula argentea, aka, Jade plant.