Lilac to prune or not to prune help

I have a huge lilac tree that has been left for years it stands about 20ft high with all the leaves and flowers on the very top of branches that look like poles...... It looks unsightly and I have taken out about a third of the growth and is starting to bud where I have pruned it... My question is whether to take it all right back to give it as much help as possible but I have had to prune everything else in the garden right back hard and it is the best bit of colour we have left even if 20ft up lol.....

 

Hi

What you have done is fine especialy with old shrubs , you can do the same next year with pruning as well , occasionaly hard pruning that leaves nothing , and nothing grows back but doing it the way you are realy helps with the survivall of the shrub

Spruce

 

Have the same problem (giant lilacs) so looked this up recently. Apparently they flower on 3 year old wood, so it's recommended to cut back by a third each year (as you've already started to do!). That way you'll apparently get flowers each year, albeit up in the sky.
I can vouch for the fact that you can't kill it by cutting back hard (to the base!) - there's loads of new growth coming up from the ground on the one I started to cut back a month ago. And at the back of the garden there's a large cluster of about 50 thin trunks (20ft tall...) interspersed with short stumps - obviously the previous owner was trying to keep it in hand but eventually gave up! It's a menace to be honest!

 

I agree with Spruce and Sadowska. With pruning, however harsh you are, you will get new shoots from the base, which will rejuvenate and eventually take over from the older parts you have now.

 

I inherited 3 lilac trees, all in a row on the edge of my garden. I don't want to get rid of them as i like the greenery sheltering me from the road and the neighbours! Three is a bit much, though, as they create a lot of shade.

They all have stout trunks to about 6', and then they branch and reach to 15 to 20'. I have started pruning them hard on a rolling programme. Most years i cut one tree back hard, leaving the trunk and about 2' of branch on top of that. I did one about 6 weeks ago and it is already starting to resprout. It looks a bit grim when first done, but soon acquires a mop of fresh foliage.

In subsequent years I allow the shoots to develop but thin them out as too many of them tend to grow. The trees will not flower the first spring after cutting back but they do develop extra large, lush foliage which makes up for it. They flower fine the year after that. One disadvantage is that hard pruning encourages them to send up suckers in the vicinity.

I agree with the policy of cutting out a third of the shoots each year - but if you really, really want to reduce the overall size you will have to give it a severe chop, but you will only miss one year's blossom.

As for the one with multiple trunks, I think I would select one good upright one to grow on and cut out the rest. I quite like my lilac trunks, they are nicely gnarled and textured. Lilac has an inclination to sucker and bush out low down, though, so it may be reluctant to form a tree at this stage.

 

I don't think that's right? I think they flower on last-year's-wood - so if you prune after flowering you will get flowers on any growth that is made in the current year.

But I stand to be corrected

 

That's exaclty what I do for the Lilac next door, one third every year (plus a vase of fragrant flowers whilst it's in bloom) in late autumn and I also get to keep the pea sticks for my trouble.

I'm thinking of shoots coming up from the base that need about 3 years before they start blooming and taking over from the larger branches that I remove, normally right down to ground level. Otherwise I'm sure the flowers are off of last year's wood.