KC Gardens

Lilacs – the smell of spring


Tip of the Week

Close your eyes and breathe in the smells of spring. If you are like me, you have probably thought of the sweet fragrance of the old-fashioned lilac. Getting a whiff of its sweet perfume is sure to put a smile on your face.

Lilacs have long been a part of our American tradition. According to the Arnold Arboretum of Harvard University, there are accounts of Thomas Jefferson planting lilacs in his garden in 1767. George Washington noted that he transplanted existing lilacs in his garden on March 3, 1785. Lilacs have been and always will be a part of Americana.

This much-beloved plant does generate a few questions. One of the most common is when should they be pruned. Lilacs bloom on old wood. The flower buds are set during the summer for flowers the following spring. For that reason they are best pruned after flowering. Pruning is best completed within six weeks of bloom. That allows enough time for new wood to grow and flower buds to develop.

How to prune is another question. There are basically two methods of pruning. One is to remove about one-third of the oldest, woodiest canes to the ground each year. This produces new shoots from the base that results in numerous blooms. This method of pruning can be used to control size. The other method of pruning is to cut very overgrown bushes back to about 1 foot from the ground. This is called rejuvenation.

Why doesn’t my lilac bloom? The most common reason is shading or lack of sunlight. Lilacs require full sun, at least six to eight hours per day. Shadows cast by trees in the afternoon will even reduce blooming. The old fashioned types are fussier about sunlight than some of the smaller dwarf varieties. Heavy pruning can also reduce flowering.

Should I apply lime around my lilac to get it to bloom? The answer is no. It is true that lilacs prefer a higher pH soil. The good news is most of our soils already tend to be high, which is perfect for lilacs. The teachable moment here is never to apply lime to any Kansas City soil unless a soil test indicates the need.

The best time to transplant a lilac is in the late winter before growth starts. And yes, you can simply cut off a portion of the bush or a shoot that has emerged and transplant without moving the entire shrub.

Enjoy this old-fashioned plant in the coming weeks. Breeding has resulted in numerous shades of lilacs ranging from the true lilac to darker shades to whites and even some the color of white and lilac. It just makes my day to walk past a lilac in bloom as it says welcome to spring! I have already picked up a new one to plant this spring in my yard.


  1. 1 year ago

    Great information! I love lilacs and I have five bushes planted in my yard. They remind me of my childhood and walking along Jayhawk Blvd on the campus of KU during my days as a student. Next to Iris flowers and their sweet fragrance the lilac is my favorite flower! I wish I could bottle it and take it out on cold Winter days to remind me of Spring days to come. Thank you for writing this post!

  2. 1 year ago

    Thank you for taking the time to comment. I have smelled man-made bottled scents and it just doesn’t smell the same. Just to sweet. Wait a few more weeks and the smell will be back. Dennis

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