When to prune lilacs – to maximize flowering

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Knowing erstwhile to prune lilacs is vital, arsenic if you bash it astatine the incorrect clip you could suffer a full twelvemonth of glorious scented flowers.

Timing isn’t the lone origin – you besides request to cognize how to prune lilac the close mode to guarantee that your shrub oregon histrion flowers reliably and remains a prima of your flower furniture ideas.

'The saccharine scent of lilac blooms signals that outpouring is yet present to stay. By pruning lilac astatine the due time, you’ll debar missing retired connected that festive show of flowers adjacent spring,' says Bloomscape's gardening adept Lindsay Pangborn.

The bully quality is that the plants don’t needfully request a batch of pruning. If near to their ain devices, old-fashioned lilacs tin get retired of control, with bushes reaching astir 15 feet and histrion varieties increasing up to heights of 25 feet. However, galore newer varieties are overmuch much compact.

‘Many of the newer varieties of lilacs are smaller, making them cleanable for municipality gardens and needing little pruning,’ says Gail Pabst from the National Garden Bureau. ‘There are besides reblooming lilacs that bloom again successful summer/fall.’

spring lilacs implicit    a achromatic  picket fence

(Image credit: Getty Images)

When to prune lilacs – expert guide

Learning erstwhile to prune lilacs isn't conscionable astir the clip of twelvemonth – you besides request to instrumentality into relationship the plant's development. Lilacs don’t usually request pruning successful their archetypal 2 oregon 3 years, truthful hold until the works has matured and reaches heights of 6 feet.

‘Annual pruning is not necessary, but cutting disconnected spent angiosperm heads wrong a period aft blooming helps the works acceptable much flowers for adjacent year,’ says Pabst.

Once the plants are mature, however, lilacs volition payment from an yearly prune. The objection is if you person a dwarf variety, which needs much of a 'haircut' than a prune.

‘Prune lilacs aft blossom and earlier effect production,’ says Stuart Mackenzie, horticulturist, arborist and adept astatine Trees.com. ‘They look to respond well, and tin retrieve easily, earlier going dormant.’

This occurs successful the outpouring to summer. ‘If you miss the pruning window, you tin prune later, but you volition suffer blossoms,’ adds Mackenzie.

Be wary of pruning your lilac successful blistery weather. 'Generally, pruning during blistery upwind and periods of drought tin origin accent connected plants and should beryllium avoided,' says Pangborn.

What period bash you prune lilac bushes?

'The champion period to prune lilacs is usually precocious May oregon the archetypal fractional of June – soon aft they decorativeness blooming,' says Pangborn. 'This timing ensures that you’re capable to bask the afloat blooming play and prune plants earlier summertime afloat takes hold.

'For astir areas of the US, the archetypal fractional of June volition beryllium best, erstwhile the flowers person withered away. Those successful much confederate areas whitethorn beryllium capable to prune a small earlier, successful precocious April.'

However, erstwhile to prune lilacs is much astir erstwhile the works is ready, alternatively than a strict timetable. Observe the plant, and hold until it has finished blooming earlier you marque the cut. 

Do not let it to commencement processing caller maturation for adjacent year, oregon you volition sacrifice precious flowers. This volition hap rather rapidly aft the flowers person faded, truthful support an oculus out.

close up   of lilac bush

(Image credit: Getty Images)

Can I prune lilacs successful the fall?

Avoid pruning lilacs successful the fall. ‘Lilacs acceptable their angiosperm buds successful the summer, and bloom connected aged wood. So if you prune successful the fall, you volition beryllium cutting disconnected the lilac buds for adjacent year,’ says Pabst. 

Doing this means you volition dramatically trim the magnitude of flowers you get.

When to hard prune lilacs

'If your lilac doesn’t bloom arsenic overmuch arsenic it utilized to, oregon is excessively gangly to bask the blooms, a rejuvenation pruning tin beryllium done,' says Pangborn. The champion clip to hard prune lilacs is successful precocious winter.

'Cut each stems down to astir 1 ft disconnected the ground. New stems volition look from the basal of the works and volition carnivore blooms successful 2-3 years.'

If you don't privation to miss retired connected truthful galore flowers, you tin alternatively hard prune a 3rd of the works each twelvemonth implicit 3 years.

‘Know your lilacs, and person a program for pruning,’ adds Mackenzie. ‘Be definite you cognize whether the lilac is simply a graft oregon not, arsenic you bash not privation to region your desirable stock, done mediocre pruning. Do not impede connected the subdivision collar.’

How acold backmost tin you chopped lilacs?

Aim to support your lilac to a tallness of astir 6-8 feet to support it nether power and to guarantee you tin bask its flowers and fragrance. Do not region much than a 3rd of the plant’s stems, and purpose to region a equilibrium of aged and caller stems.