Answer: It seems odd that neither of your forsythia have bloomed. They typically grow well in both sunny and partly shady sites so I don't think their lack of bloom is due to exposure to sunlight. I would prune both shrubs back hard in mid-May. Flowers form on prior year's growth, not new growth. You can cut back old growth to as far as four inches from the ground. Don't hesitate to be aggressive in pruning these fast growing plants. The new growth they produce this summer should bloom for you next winter and you can prune them back again next spring for the following year's bloom.
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