Q: The lilac bushes that I planted in 2009 did not bloom last year and only had three buds the year before. They have doubled in size in that time and have had plenty of leaves , so I know they’re healthy, but they don’t bloom. Any idea why? — Jim D
A: There are a few reasons why your lilacs may not be blooming. Lilacs form flowers on on one-year-old plant growth. Here are some questions to ask yourself. You said you planted the bushes in 2009—were the plants a year old when you planted them? Did you have a late freeze last year? A late freeze may have prevented the flowers from blooming. If the lack of blooming was due to a late freeze, your lilac bush should be fine this year—as long as there isn’t another late freeze. The other causes may be due to lack of sunlight or pollinating insects. Does your lilac bush get adequate sunlight? Do bees and other pollinating insects frequent the area around the lilacs? Providing plenty of sunshine and an enticing area for pollinating insects can do wonders. Lastly, pests may prevent blooms from occurring. Did you notice any pest damage on the tree? By process of elimination you will most likely be able to solve the mystery of your non-blooming lilacs.
The good news is that all of these reasons for non-blooming lilacs are easily corrected.
2013 update: By process of elimination, we determined that our lilac bushes was not getting enough sunlight. Following Shelley’s advice, we moved them to a much sunnier location, and this year they have buds on almost every branch. Thanks for the help! –Jim D