Common Lilac

Posted by shane - January 7, 2015 - A-Z Plant Maintenance, Shrubs - No Comments

Syringa vulgaris

Common lilac in flower in Red Deer.  S. LePage photo.

Common lilac in flower in Red Deer. S. LePage photo.

This is one of my favourite shrubs, despite its propensity for suckering and potential for high-maintenance. Common lilacs are ubiquitous, rock-solid hardy, insect and disease resistant, supremely drought-tolerant, and essentially bomb-proof.  Actually, if someone let off some explosives on a lilac, I’m sure it would happily “sucker back” the next year and create a lovely shrub.  It is available in a range of colours from light to dark purples, to blue, pinks, and white. Lilacs have many uses, from the traditional wind-break on farms, to specimen plantings in trendy, inner-city front yards, to privacy barriers in back-yard gardens.  Common lilacs make excellent hedges, either formal or informal, and I consider a properly manicured lilac to be the best hedging material on the Prairies, eclipsing cotoneaster and caragana due to its disease-resistant nature.

A hand-sheared lilac hedge in Ponoka.  S. LePage photo.

A hand-sheared lilac hedge in Ponoka. S. LePage photo.

Exposure

Full sun

Pruning Time

Depends on the application and your tolerance for maintenance.  Formal hedging should be carried out after the growth flush, preferably mid-summer onward.  The hedge will likely need a touch-up trim in late summer to keep things looking neat.  Prune anytime for specimen reinvigoration, although I always prefer to prune lilacs when the leaves are off so I can see what I’m doing.

Informal hedge-barrier in Calgary.  S. LePage photo.

Informal lilac hedge-barrier in Calgary. S. LePage photo.

Pruning

Most commonly, we are called upon to clean-up or “reinvigorate” overgrown specimens.  This means we remove the majority of the suckers and deadwood, selectively thin the stems from the base of the plant, and create an attractive, clean-looking shrub, with a pleasant “snow-cone” shape. This is tedious, time-consuming work but will transform an ugly, old lilac into a show-piece of the garden bed.  It is worth the effort.  If kept up annually, the pruning is minimal, a few suckers at the base and a bit of deadwood.

Ideally, trim formal hedges with sharp, long-handled hand shears, as opposed to the power hedgers.  For budget and time constraints, we often use power hedgers followed by a quick hand-shear touch-up when working for clients.  On my own hedge, I would spend the time and effort and use shears only.  They make a nice, clean, scissor-like cut, and the edge of the leaves won’t “brown-off” after trimming.

If you want a privacy screen but don’t appreciate the bulky width of a mature lilac, try trimming only the sides of the hedge but leave the top alone.  To me, this will give you the best of both worlds: a neat, crisp side-cut, with a beautiful, fragrant, flowering top.  A mature lilac will max out around 15′ tall, so this method gives you a great privacy wall to block out a bad view or unfriendly neighbour.

Lilac base before reinvigoration pruning.  S. LePage photo.

Lilac base before reinvigoration pruning. S. LePage photo.

Lilac base after pruning.  S. LePage photo.

Lilac base after pruning. S. LePage photo.

 

 

 

 

 

 

 

(c) 2015 Shane LePage, Wild Rose Garden & Tree Service Inc., Red Deer, AB