Prune the drawn out branches
Use sharp secateurs to shape your forsythia bush by trimming off all its branches that are sticking out from the desired shape. However, make sure to cut the branches right back to their main stem.
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Prune the whole stem
If your forsythia bush is totally out of shape and if think that pruning wouldn’t work for you to enhance its appearance, trim it off from the bottom. All you have to do is, use loppers to cut the whole bush back to within 4 to 6-inches of the ground. It provides you with an opportunity to continue your plant’s growth in the desired shape once new growth comes in.
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Consider Renewal Pruning
This pruning is perfect for a standard forsythia bush. Clip less than a third of the branches or canes. Repeat this type of pruning after every three to four years, or as needed.
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Prune the suckers and runners
Grab the secateurs and cut off all the runners or suckers all round the bottom (stem) of your forsythia bush. They can make your plant look messy and absorbs its essential nutrients.
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