When and how do I trim or prune lilac trees?

prune em right after their flowers fade in late spring and no later cuz they will use the rest of the growing season to %26quot;set%26quot; buds for flowers next spring. if they%26#039;re like the rest of us, they got hit by that late freeze and it killed all the buds before they could even open..... so sad!

When and how do I trim or prune lilac trees?
I%26quot;m not exactly sure but I hope this may help you in that direction.


By Lindsay Bond Totten


Scripps Howard News Service





Love it or hate it, pruning is an important late winter task. Gardeners do it to improve the looks of their ornamental trees and shrubs. But good cuts go deeper. Proper pruning techniques can mean the difference between life and death. And that%26#039;s the horticultural truth, so help my Felco%26#039;s.





Good pruning is the horticultural equivalent of preventive medicine. It doesn%26#039;t necessarily assure good health -- other factors do play a role -- but it can extend the useful life of landscape plants. Statistics would be helpful here, but longevity, based on pruning alone, is hard to qualify. Personal experience and observation suggest that well-pruned plants can last at least twice as long as poorly-pruned specimens, and sometimes much longer.





Lilacs, rhododendrons, leatherleaf viburnums and other coarse plants seem to succumb most rapidly to poor pruning. Sparse, thick twigs and widely-spaced buds don%26#039;t forgive pruning cuts graciously. Topped branches respond with long lanky growth. Old stems become bare at the bottom and exposed branch stubs are ugly all winter. If intended for screening, such poorly pruned shrubs quickly lose purpose. In just a few years they may need replacing because they%26#039;re not doing their job.





Dense, twiggy shrubs like spiraea, azalea and deutzia are stressed by repeated shearing. Within a few seasons, energy reserves are depleted from loss of foliage. Shrubs develop dead spots. They look tired and worn out too soon. Part the branches of a sheared shrub this spring and examine the inside. The inner twigs look dead, don%26#039;t they? Only the tips of the stems have any leaves. Renewal pruning is possible in some cases, but it%26#039;s a time-consuming chore that requires know-how. Many people opt for costly replacement instead.





Though pruning is one way to control plant size, it%26#039;s not a good plan to reply on consistent heavy pruning to keep plants small. Crabapples and magnolias, for instance, stubbornly resist taming. Removal of major branches is countered by these species with vigorous shoot growth the following season. Shoots -- or %26quot;suckers%26quot; if they arise from the ground -- defy the tree%26#039;s normal branching pattern and grow straight up into the air. Cutting them just results in more shoots. In winter, poor pruning is laid bare. Thick stubs and tight bunches of unattractive shoots reveal the tree%26#039;s bad haircut.





On the other hand, neglect is not good either. That%26#039;s especially true of multiple-stemmed plants like lilac, mock orange and beautybush. As these shrubs age, old stems grow less productive. Thick woody trunks become bare at the base while leaves and flowers are carried only near the top on new growth. When a trunk dies, perhaps from insects or disease -- or just old age -- vigorous young shoots are unlikely to replace it unless a pruner%26#039;s hand intervenes.





Good pruning, just like preventive medicine, helps ornamental plants grow old gracefully. An annual %26quot;checkup%26quot; should include:








Light thinning: Remove just a few of the larger branches at any one time to let light and air reach the center of the plant. This insures more flowers and healthy growth while increasing the length of the stems without stimulating excessive shoot growth.





Moderate tip pruning: Vary the lengths of tip cuts to leave the plant looking natural instead of sheared. (Hedges are the only shrubs that require shearing.) Always cut to one-fourth inch above a lateral (side) twig to avoid leaving a long stub.





Gentle renewal pruning: Each spring, remove about one-fifth of the oldest, craggiest trunks of multiple-stemmed shrubs. Renewal cuts are usually made at the ground. This five-year cycle keeps older plants forever young, easily lasting the lifetime of the person performing the pruning.





Sanitation: Get rid of dead and dying branches to remove the source of infection and improve the plant%26#039;s health and longevity.


(Lindsay Bond Totten, a horticulturist, writes about gardening for Scripps Howard News Service.)
Reply:I%26#039;ve seen lilacs blooming that have not been pruned in 20 years or more and they do just fine. Yes, they do get tall, but boy do they put on a show!


.


So, if you must prune to maintain shape and size, do so only after they have stopped flowering. This is true of all flowering shrubs by the way.


.


Remove branches back to the main trunk and if you remove a trunk, remove right to ground level.


Remove any dead wood


Remove any branches that cross or interfere with each other.


Remove all the old blossoms. I%26#039;ve done this, but I%26#039;ve not noticed any improvement in blooms.


My best result came from making sure they had water during a dry spell, lilacs are native to Persia and the desert, but they really seem to respond to adequate water supplies.


.


Then stop!


Wait a day or so, looking at the shrub at different times will keep you from over pruning and making mistakes.


.


One rule for the older species is that you can remove up to one third of the uprights each year to encourage new growth.


New species don%26#039;t send up suckers which means you can%26#039;t cut out any of the original trunk stock.


.


Another point about lilacs is to prune them away from buildings to increase air circulation around them. Lilacs are prone to powdery mildew and mold, so it%26#039;s best to plant them in an open space.
Reply:The best time to trim is in late spring when they have finished blooming of in the fall. You want to prune off all the dead ends and seed clusters to keep it blooming at its best. If you are going to do major trimming, best to do it in late spring so that it can form new buds for next spring.



super nanny