Lilac pruning to maintain size

I have a lilac that's about 2m tall, and I want to keep it about that size, but probably a bit more filled out.

I read that one prunes off the old flowers after they finish, however I now see already that the side shoots below the flower are going to make the plant significantly taller each year. (see picture)



What's the approach to try and maintain the previous size?
Thanks!

 

Cut it back to about 1.5m after flowering and repeat each year, that should keep it to the size you want.
No need to be fussy about it, just cut it all back.

If it's a multi-stemmed shrub, then remove about 1/3 of the oldest stems and that will encourage new stems to grow from the ground.

If it's not a big bushy shrub, don't prune such that most of the leaves are lost - I done that to one of mine and it died so I cut it back to the ground. Fortunately I didn't dig it up and the following year new shoots appeared from the stump that was left.

 

So you're saying that even if I cut back to last year's growth, that will all bud again next year?

 

It won't flower as well as if you left it alone, but pruning just after flowering should allow new flower buds to appear this year, ready to flower next year - but it may not flower as well as usual.
So it's a balance between keeping it to the size you want and getting flowers.

I know when I've hard pruned one of the 2 lilacs I have, sometimes I get no flowers the following year or just a few.
You may want to consider an alternative shrub that you can keep to 2m.
There's one in a neighbouring garden that's a good 15ft and that was smothered in flower spikes recently.

 

Lilac naturally wants to grow into a sizeable tree so it sounds like wrong tree in the wrong place.

 

I believe Monty did a segment recently on cutting back Lilac. If you have access to BBc i player check it out (I think it was a couple of weeks ago?)