Pruning Lilacs

 

Star-Tip 1039

Gardening Tips for successful and beautiful Landscapes and Gardens

 

To optimize the beautiful shape of your lilac bushes, you need to prune them each year. Pruning is a very important part of growing and caring for Lilacs. While some varieties only grow 4 to 8 feet, others can reach up to 30 feet tall. Most will grow in excess of 10 feet. Pruning will not only help with shape and appearance, but also impact plant health and vigor and the profusion of flowers.

Appropriate Techniques

How Often to Prune?

Maintenance Pruning

Sketch for Maintenance Pruning Technique

Dealing with an overgrown or neglected lilac

Three Year Rejuvenating Plan

Hard Pruning - A more drastic solution

 

 

Appropriate Techniques for Pruning Lilacs

There are right and wrong ways to prune a lilac. There is also a right and a wrong time. For maximum beauty it is most important to prune your bush immediately after they are done blooming during the growing season. Make sure to remove the spent bloom with your clippers. This will keep the plant from growing seeds and encourage creation of next year's buds.

r Seasonal pruning should be done as soon as the flowers have faded.

r Cut small suckers and shoots at or near ground level, or where it comes out of the main trunk. It is okay to clip off old, dead flowers at the base.

r Leave a few strong and healthy new stalks each year, especially if you are planning to trim back old wood. (top)

 

How Often to Prune?

Lilacs should be pruned and maintained each year. The plants should be full looking, yet not overly bushy. If the plant is too bushy, the inner leaves do not get sun and air circulation. A lack of oxygen to the plant is an invitation to plant disease.

 

Trim larger stems from the center of the bush to increase ventilation. It will also afford more room for newer shoots on the outside of the plant to develop.

 

 

 

Next year's flower bud develops early, even though you may not see it. Often an inexperienced gardener may trim the tops several inches back. While the plant might look a lot nicer, they loped off the next year's flowers with one pass of the hedge trimmer. By the way, avoid using hedge trimmers. It gives a too trimmed appearance. Lilacs are not hedges.

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Maintenance Pruning

First of all, maintenance pruning involves removing all dead or broken wood, branches that are less than 10” from the ground.  Also, branches too curved or too close together and any that are rubbing or crossing.

By removing some of the weaker, old and less vigorous branches each year, maintenance pruning is also a way to rejuvenate a shrub. Removing branches gradually won’t radically alter the shrub’s appearance and, since it may take the new stems up to five years to bloom, your lilac will continue to flower each year. On grafted plants, it is important to keep only those branches growing above the graft union. On others; Suckers that form at the base of the tree every year can be selected to replace the main branches. Choose a few of the strongest suckers and get rid of the rest. (top)

 

Sketch for Maintenance Pruning Technique

Trim back any branches that stick out from the main bush, and that are not appealing to you.

Topping your lilac is not encouraged. Generally a flat top is less appealing. A slightly rounded top looks great and helps promote better flowers.

 

In trimming and pruning your bushes, remember, beauty is the eyes of the beholder. If you like a tall bush let it grow tall. If you prefer a wide bush, encourage shoots that have spread out from the main bush. (top)

 

Dealing with an overgrown or neglected lilac

If a lilac bush has become overgrown, or is too large or tall for the area you have allotted it, there are a couple of ways to get it back in shape.

 

Three Year Rejuvenating Plan

The three year plan is very popular. A lilac shoot takes about three years before it produces a flower. So plan to eliminate 1/3 of the shrub each year, selecting the oldest stalks. Cut them down to just above the level of the soil. As you do, allow new shoots to grow to replace the old ones. By the end of three years, the entire shrub will have been replaced, and you will not go without lilacs for that period of time. Then, continue the cycle each year. (top)

 

 

 

Hard Pruning - A more drastic solution

If life with your overgrown shrub has just become unbearable, remove all old stock and leave just new shoots.

 

Do this during the winter, when the plant is dormant.

 

This is pretty drastic. And, you will go a couple of years without lilac flowers.

 

But Lilacs are hardy. As long as there are a few healthy new shoots, they will grow back.

 

 

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