Trimming Lilacs?

Question

My mother would like to trim her lilacs, she has a row of about 10 that are about 20 years old. They need to be about half their size. What is the best way to cut them? We have heard that cutting them can cause them to stop flowering for good which obviously she doesn't want. Should she cut them or let them keep growing? She's really nervous, they used to be my grandmothers. Specific answers would be great! Thanks!!!

I would estimate they're about 10 feet tall, and very pretty. She's afriad they look too unkempt.

Answer 1

cutting back substantially will decrease next year's bloom, since lilacs bloom from this wood. but they will bloom profusely in following years, so the tradeoff may be worth it.

lilacs are hardy enough to withstand most pruning. your local nursey can provide you with information particular to your location, and the cultivar of lilac your grandmother has.

i'm glad you're concerned... nothing says summer like a fragrant bouquet of lilacs...

Answer 2

older lilacs may need 'rejeuvenating'.... and the pruning to do that is simple.... takes a while, tho.... this late fall, after a few frosts have taken the leaves off, take out old branches TO THE GROUND... one third of all the branches..*the plant will put out new little sprouts at the base.. let them grow on)....... then wait until after the plant has flowered the next spring, to cut BACK the whole plant by one third in size..... the next late fall/winter, take out another one third of the older branches and in spring , after flowers have faded, cut back for size again if needed..... then do this one more time the third year and take out whatever old wood is left, to one third of the shrub.... again, after bloom, prune to size..... at that point, the whole bush is new sprouts, new wood and should be thick and full and flowering especially nice!!!.... and you'll not see a year where there is NO blooms, either!!... after the whole three years, all she'll need to do is take out a branch or two every now and then to keep the new little sprouts coming up and to take out the oldest wood.....

Answer 3

Your mother should trim her lilacs, because keeping them "open" (thinned out a little) helps to prevent disease. However, she must trim them right after they flower because the new growth is where next year's blooms will be, so if she waits until well after the flowering period has ended to trim, she will effectively be eliminating next year's flowers - and nobody wants that! So, yes - do trim, but immediately following flowering. Best of luck.

Answer 4

To be sure I would ask a landscape place. I don't think you should cut them back at all. I have never seen anyone cut them. Ask an expert. Grandma's Lilacs are not worth just asking us. Would not be a pretty thing if you killed them or they didn't flower again.

Answer 5

Cutting back will not keep it from blooming.