Posted by Newt on March 22, 2003 at 18:25:16:
In Reply to: Re: Lilacs posted by Vicki on March 22, 2003 at 17:40:52:
: : : We planted a lilac bush about 4 or 5 years ago. It's growing well, full of leaves and bushy however it has yet to bloom. It's about 6 feet tall now. I have never pruned it but I do know that you should prune it after it has finished blooming. Is there anything I can do to help it along?
: An additional suggestion would be to do a bit of digging around the roots. Some plants (lilac and wisteria, esp) can be prodded into blooming the following year by doing some minimal root damage. Best story I ever heard was of someone who was removing a 40 year old lilac that gave up on flowering years earlier. Chain saws and all manner of power tools were employed to oust the old timer; but the owners gave it up for the fall .... and guess what ...yep......it bloomed like mad the next year, after all the abuse.
: : Often lilacs can take 5 to 7 years to bloom from new shoots, but a nursery purchased one usually blooms within a couple of years. I don't know where you live, but lilacs like a more alkaline soil. If you live where the soil is acid, that might help to delay bloom. I live in Maryland and my lilac was near a pine tree. It hadn't bloomed in 7 years. Then I heard about the lime and it worked. The lilac bloomed the following year. Just sprinkle a cup of lime around the base and scratch in every year or two. Lilacs also like full sun.
: : Good luck,
Root pruning a lilac can be drastic and I wouldn't recommend it as a first step. The reason your friend's lilac bloomed was probably because they pruned out the old growth, allowing light to the plant. The way to rejuvinate an old lilac is to cut out the oldest trunks to the ground. There actually are several reasons why a lilac won't bloom. Here's a quote from a site that sells them.
"Why is my lilac not blooming?
If blossoms are non-existent or sparse, check for insufficient sunlight, infertile soil, too-wet ground, poor drainage, or pruning at the wrong time. A common culprit is too high a nitrogen level in your fertilizer."
"How do I rejuvenate an old lilac?
Cut out one-third of the main stems to the ground level. Follow this procedure for three or more years until the lilac has returned to an attractive and manageable shape.
This procedure opens up the lilac and permits more sunlight into the plant and brings down the height of the plant."
Here's a couple of sites that should be helpful.