Problems with Diefenbachia
Why did Diefenbachia grow in height? There is enough light, moderate watering, and do not overfeed with fertilizers. This had not been noticed before; it had not been growing very actively for three years, but then it burst through.
In the autumn-winter period, indoor plants do not need fertilizing at all. I didn’t fertilize my Diefenbachia with anything at all and it grew well in partial shade. You can replant your plant. You can cut off the top if it is very high and root it.
It is also important what exactly the flower was fed with. If it was mainly nitrogen, then, naturally, active growth in height began. In addition, it is typical for this culture to gradually stretch out. To maintain decorativeness, pruning is required.
Dieffenbachia itself is a tall plant, it is practically a tree. Of course, it needs to be trimmed. Just remember that this is a poisonous plant, and you need to protect your eyes and hands while pruning.