Answer: The most common reasons for lilacs failing to bloom are lack of sun and pruning at the wrong time. Lilacs do best in full sun all day but will tolerate a half day if it includes the hour of noon. Even in just a couple of hours of sun I would have expected to see one or two blooms. This shrub blooms on last year's growth, so the only safe time of year to prune it is right after it blooms, or in late spring. Pruning at other times removes the flowering wood or buds.
Wisteria may take a few years to become established and begin to bloom well. If it is a grafted plant with the scion taken from blooming wood, it should bloom early. If it is a seedling, it can take up to 20 years to begin blooming. Proper pruning and care can also help. Here is some general information on that.
I hope this helps!
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