Darryl

You have a most AMAZING Dieffenbachia!

Plants will always grow from their tips as older leaves fall from the lower parts of the stems.  This means the leafy top of a plant will INEVITABLY get to a point where the lower stem looks rather bare and the overall plant may even topple over.

It appears you are already supporting the stems with stakes, which is the first thing I would have recommended, but at some point, you will want to cut it back.

Just cut the main stem at the point where you want new roots to grow – this will eventually be UNDER the soil so make sure there is enough space between the main stem and the lowest leaf so the leaf doesn’t end up under the soil.  After cutting, you can put the leafy top part into a jar of water, wait a few weeks for it to form roots, then transplant it into soil.  You could cut all the stems or just one or two at a time – it’s completely up to you.

My book and my online course go over the principles of propagation as key techniques for long-term plant enjoyment!