Forsythia is a bush-type plant that produces an abundance of yellow flowers each season. If your plant produces few flowers or is growing out of control, follow these steps to prune it.
Step 1: Determine The Correct Time
Prune your forsythia either right before or right after it begins to flower. Either method will be effective, but it may be easier when you can see what you are pruning. You may lose a few blooms this season, but the bush will be healthier. You also will not need to interrupt the new growth to prune it back.
Step 2: Start Pruning
At the bottom of the bottom of the bush, cut off any stems that are closer than 4 inches to the ground. Otherwise, these branches will start to droop, plant themselves in the ground and start a rooting system for a new plant. You can force blooms on these cuttings so as not to waste them.
Step 3: Thin It Out
Rather than cut off all of the new growth on the exterior of the bush, reach inside of the plant and trim down the interior. You should cut or pull out about ¼ of the plant from the interior section. This will loosen up the bush and allow it to flow freely.
Step 4: Shape the Plant
For best pruning results, only trim the runaway chutes. Some gardeners may not choose to cut any of the outer part of the bush, while others incorrectly shape and mold the bush to fit into an area too small for the plant. The plant can grow to be up to 7 feet high and is naturally shaped like a vase.
If you find that your plant has grown completely out of control so that even pruning doesn't help, you can cut the whole plant down and start over for next season. Cut it down to the soil level, and new canes will start to shoot from the roots.
It is difficult to keep a forsythia plant down for too long. Keep the pruning under control though so that you will see beautiful blooms on your plant year after year.