I have 2 tropical hibiscus plants that I put outside in the summer and bring in the house for the winter. This summer they have been very happy and have more than doubled in size. They are each about 3 and half feet high and 4 feet wide. (see pictures). I need to cut them back some as I have no place in the house for plants that size. I love them and don’t want to damage or kill them. How do I trim them safely? Also, when should I cut them? When there is no open bloom? There are always buds. Does it matter when? Any help you can give will be appreciated.
The best time to prune a potted hibiscus is during sunny mild weather. If you plan to take your plant in and overwinter it in a sunny location, then prune it now. If you plan to overwinter it in a dark place like a cool basement or garage, then wait to prune it in the spring.
You can do a full pruning, taking each branch down to 2 or 3 nodes. This often gives the best results, producing a well shaped plant. However if you want to keep some flowers, then do a selective pruning, cutting back selected branches. If most of the branches have flowers or buds, I would remove the flowering ones so that you will have new flowers to look forward to. You do not want to remove more than 1/3 of the plant. Any time you prune, start by removing dead or damaged branches and then try to look at overall shape as you prune. There is a very good description on the site below as well as lots of information on care of hibiscus. The upside of pruning the hibiscus is that more branches will come out from the nodes and since there usually there is one flower per branch you will increase the number of flowers.
You should also consider root pruning every couple of years. Upend the pot (easier said than done by the looks of the size of your plants!) and cut off the bottom 2 inches with a sharp sterile knife. Then added a couple of inches of good soil to the top and repot your plant.
For care and pruning of hibiscus, click here.