Answer: Some lilacs take 5-7 years to mature before they will bloom. Overfertilizing, lack of adequate sunshine, pruning at the wrong time and winter kill are the most common reasons for non-blooming lilacs. Lilacs grow and bloom best in a full sun location with direct sun all day long. If your plant is growing in a shady site, that might account for the lack of bloom. Lilacs bloom on wood that grew the year before, so pruning at the wrong time can remove flower buds. The only time to prune these is in late spring or early summer, right after their normal bloom period. Sometimes lilacs will fail to bloom because of too much or too little nitrogen fertilizer. If your plant is growing in or next to a lawn that is regularly fertilized, that should be sufficient and no additional fertilizer will be needed. If your lilac is planted in a shrub bed, you might try giving it an annual top dressing of compost along with an application of general purpose granular fertilizer such as 5-10-10 per the label directions in the spring. That, along with a routine watering and three inches of organic mulch over the soil should be adequate. Don't give up on your plants just yet. Prune them back now to encourage healthy new growth and cross your fingers they will develop flower buds this summer for next spring's floral display. Good luck with your lilacs.
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