How do I prune an ancient lilac?

[warmfuzzies]

We live in a rental house in the country, that is over 100 years old. There is a lilac and a BUNCH of overgrown snowberries (I think).

The lilac bloomed beautifully last year, and is still smaller then some I have seen, it is about 8 feet tall and around. It looks really straggly to me, and I was surprised to see it bloom so well.

Should I prune it or leave it? I have read that lilacs need the old growth pruned off every few years to keep blooming their best. I don't know how old it is, but it seems to have a lot of old wood on it.

This property is one of those that is maintaned living-wise only, they do nothing for any of the plantings or yard. I am sure they would not care either way if we pruned it or not.

 

[4grandbabies]

I love those beautiful old lilacs! I had one at another home place a few years back, it developed a white virus on its leaves. I was told that it was because we did not clean out the leaves that gathered at its base well enough. I dont know if that is true or not, I cant answer about pruning --- just thought I would throw in that extra info. Have you thought about taking some cuttings and starting a bunch more ? I will be following this because I want to start lilacs again, and want to do it right this time.

 

[journey11]

Not hard at all! Wait until spring, right after the lilac has just finished blooming before you do anything......

Then, what you want to do is nuture the newer growth, because that's where all your bloom is going to be. You don't want to do too much pruning all at once though.

Every year, after the blooms are spent, first thing you want to do is clip off all the spent blooms so that they will not waste the bush's energy trying to make seed.

Then, next you want to look at your clump of branches and cut out only the very biggest ones, about 20% of the total volume of the clump. Lilacs make new suckers every year (you can even divide some of these outter most ones and propagate new bushes if you can get a little root with it). These suckers are going to eventually be the flowering branches of the plant. They bloom best on second year growth. So every following year, repeat this process, cutting out the 20% of the biggest branches, and allowing new suckers to come up. Of course, you can cut out any dead growth too. (Once you get that monster under control, you can let it go a couple years before you thin again.)

This will help your lilac stay healthy too, by giving it good air circulation and letting the light in.

You can do a light pruning around the top to control the shape a bit, but I recommend that you not get too carried away with that, or you'll forfeit a lot of next year's bloom!

I've seen some people try to prune their lilacs into a tree-like formation, but you give up a lot of precious bloom. Really they are most spectacular if you let them form a giant clump, IMO.

 

[boggybranch]

Just be sure to use ancient pruning sheers. LOL

 

[warmfuzzies]

Ok thanks guys! That sounds managable. And, yes, all I have are ancient pruning shears, so I am sure that is what I will be using.

 

[nickslawnandgarden]

Not hard at all! Wait until spring, right after the lilac has just finished blooming before you do anything......

Then, what you want to do is nuture the newer growth, because that's where all your bloom is going to be. You don't want to do too much pruning all at once though.

Every year, after the blooms are spent, first thing you want to do is clip off all the spent blooms so that they will not waste the bush's energy trying to make seed.

Then, next you want to look at your clump of branches and cut out only the very biggest ones, about 20% of the total volume of the clump. Lilacs make new suckers every year (you can even divide some of these outter most ones and propagate new bushes if you can get a little root with it). These suckers are going to eventually be the flowering branches of the plant. They bloom best on second year growth. So every following year, repeat this process, cutting out the 20% of the biggest branches, and allowing new suckers to come up. Of course, you can cut out any dead growth too. (Once you get that monster under control, you can let it go a couple years before you thin again.)

This will help your lilac stay healthy too, by giving it good air circulation and letting the light in.

You can do a light pruning around the top to control the shape a bit, but I recommend that you not get too carried away with that, or you'll forfeit a lot of next year's bloom!

I've seen some people try to prune their lilacs into a tree-like formation, but you give up a lot of precious bloom. Really they are most spectacular if you let them form a giant clump, IMO.

You can actually heavy prune lilacs unlike some plants. It will just come down to how much it has in reserves. Like you said if you want to worry about blooms right now then be lite on the pruning.
If you choose to prune heavy (which I recommend) then be prepared to not get any blooms for a while but the end results will be great! Also if you rent the house you may not want to heavy prune.
Good luck!