The Paranoid Pruner Part Two: Overgrown Lilacs

(Read the first Paranoid Pruner post here.)

The best time to prune lilac bushes is after the flowers have died off as the bush sets its buds for next year at this time (but you may not actually see them). Now, bush, is the key descriptive word because my lilacs were starting to look like small leggy trees with most of the fragrant flowers blooming well above my head. In this case, “legs that won’t quit” is not good! Luckily, old lilacs are easy to revive as they give out plenty of suckers to stay alive for centuries. However, for thriving lilacs, occasional pruning is needed.

Before shots (Please note: I'm on year two):


Lilac #1




Lilac #2

The Three-Year Period Method of Reviving an Overgrown Lilac

Lilacs bloom best when there is a balance of old and new shoots. Old shoots larger than 2” in diameter should be removed. Know that new shoots won’t bloom in the first few years, it takes about 3 years—the same length of time one generally needs to revive an old, overgrown lilac—one needs patience when gardening. If your lilac bush is too tall, it is not a good idea to just cut off the top, instead remove the old stem. To cause branching (resulting in a bushier look) prune remaining stems to an outward facing bud. Leave some healthy new shoots, pruning the rest at or near the ground level or where it comes out of the main truck. It is especially important to leave some new shoots if you are also removing a lot of old growth or you won’t have a bush left!

In general, you don’t want to remove more than a third of the stems any given year (some years will require much less). Anywhere between 8 to 12 stems of varying age (1” – 2” in diameter) is a good rule of thumb for a lilac bush to thrive. This allows for proper air circulation and for inner branches to enjoy the sun, too.

As always, remove any dead or diseased stems, twiggy and small suckers, branches that crisscross or rub up against other stems.

With careful pruning, an old lilac bush should have all new stems in three years. I have read conflicting opinions on whether or not to deadhead spent lilac blooms. I have read that old bushes do not need this treatment, but I also read that it keeps the plant from setting seeds and encourages next year’s buds.

I saved all the cut branches to use in the garden as stakes, trellis etc., as needed. ( I just remembered that I have a third lilac bush to prune! It's in a very overgrown section of the garden--yet another project, but I don't want to talk about that one.)

After:

Where did they go? I hope they will get bushier with all this pruning!

In case you're curious, that is our garage in the background (yes, it's big), the outdoor shower, another reclaiming garden project (suppressing Gout weed, thinking of planting sage in its place), and rusted metal things that the hubby likes to decorate the yard with!
Sources:

http://www.ipm.iastate.edu/ipm/hortnews/1993/2-10-1993/lilac.html

http://www.gardenersnet.com/lilac/lilac02.htm

http://gardening.about.com/od/pruning/a/Pruning_Lilacs.htm