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Pruning Shrubs Pruning basics

What to prune 1. Remove dead wood, crossing branches, down-

ward branches, watersprouts

2. Remove old unproductive wood

3. Create more air, light and space in the center

4. Shape and size

Where to cut and how

Type of cuts

1. Thinning (cutting back to side branches, thins out as it doesn’t stimulate side

branching)

2. Heading back (cutting back to buds or between buds, promotes side branching and a

denser plant)

3. Gradual rejuvenation (removal of 1/3 of oldest stems to the ground each year)

4. Complete rejuvenation (cutting back all branches to the ground)

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When to prune ; This depends on whether the shrub flowers on new growth from this year or on old

growth from the previous year!

1.Shrubs flowering on previous years growth generally flower before the end of June

and should be pruned immediately after flowering thus giving time for new buds to develop

Amelanchier (Serviceberry) Genista

Aronia (Chokeberry) Lilac (Syringa)

Azalea (Rhododendron) Mockorange (Philadephus)

Early flowering Spiraea (Bridal Wreath) Magnolia

Flowering Plum (Prunus triloba) May Day Tree (Prunus padus)

Flowering Cherry (Prunus tomentosa) Viburnums

Forsythia Weigela

Privet Wisteria

2.Shrubs flowering on this years’ growth generally flower after the end of June and

should be pruned in the early spring before growth starts

Annabella Hydrangea Summer flowering spiraea (mostly pink varieties)

Hypericum Snowberry (Symphoricarpos)

Hydrangea (Paniculata) Summersweet (Clethra)

Roses Potentilla

Buddleia

3.Shrubs grown primarily for their foliage and fruit rather than showy flowers should be

pruned in the spring before growth starts

Alpine currant (Ribes) Euonymus

Barberry (Berberis) Ninebark (Physocarpus)

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Blueberry (Vaccinum) Smokebush (Cotinus)

Dogwood (Cornus) Sumac (Rhus)

Elderberry(Sambucus) Winterberry (Ilex)

Although pruning can be done anytime during dormancy (late fall - early spring when temperatures

are above 20F) The open wounds from late fall and winter pruning might result in some winter

damage and die back, so early spring is better. Shrubs flowering on previous year’s growth will

have fewer flowers if pruned at this time as these flower buds will be pruned out, so after flowering

is better in this case.

If in doubt about what to prune in general just remove some of the oldest stems at the ground. Trim

back any over -long stems to a side branch and remove any spindly weak growth.

Pruning Chart

Pruning chart

Name When to prune How to prune

Berberis (Barberry) Early spring Actually flowers on old growth but flowers are insignificant and is therefore

pruned in the spring. Generally little pruning needed. Cut back some of oldest

branches to the ground each year. Overgrown plants can be cut back entirely to

ground level to rejuvenate.

Used as hedges where it can be sheared.

Blueberry Vaccinium Early spring After planting for the first 2-3 years remove fruit buds by cutting off the tips

(2-3”) of previous years growth (early fruiting stunts plants). Subsequent years

remove low growing branches and any weak spindly growth. Head back

overlong branches to 4-6” below top of bush. As plants reach about 5 years of

age remove a few of the oldest canes each year.

Clethra (Summersweet) Early spring Flowers on new growth. Cut back any overly long stems, periodically remove

a few of the oldest stems at the ground.

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Cornus (Dogwood)

Shrub

Pagoda dogwood

Shrub-tree form

Early Spring before

bud break

After flowering

Since new growth has the most vibrant color, cut back older stems to the

ground each year. Long whips should be headed back to encourage branching.

Flowers on previous year’s growth. Little pruning needed, Shape as shrub form

or single or multi stemmed tree. Lower limbs are removed to convert a shrub

into a tree.

Diervilla (Honeysuckle) Early spring Cut back oldest twiggy stems to ground every 3-4 years

Euonymus (Burning

Bush)

Early spring Usually doesn’t need any pruning. But if it has become too big which is often

the case it can be completely cut back to 1-3”. They can also be sheared, often

to a globe shape or as hedges

Forsythia After flowering.

Pruning too late

will remove next

years flower buds

Flowers on previous year’s growth. Don’t prune for several years after

planting. Cut up to 1/3 of old growth to the ground to stimulate new branch

growth. Pinch off tips of new shoots when they are 1 – 2’ long and head back

long whips by 1/3 to stimulate branching and to increase next year’s flowers.

To renew an old neglected plant cut back to 6-12 “, old woody stems should be

cut to ground level.

Hamamelis (Witch

Hazel)

Late fall after

flowering

Little pruning needed. Thin out old stems of interior if it becomes crowed.

Hydrangea arborescens -

Annabelle etc

Early spring before

bud break

Flowers on this year’s growth. The dry flowers add winter attraction so spring

pruning is often preferred. Cut all branches to the lowest pair of strong buds

which can be anything from 6-18 inches from the ground. The closer you cut

to the ground the larger the blooms will be, but less sturdy stems, hence a

floppy shrub.

Hydrangea paniculata –

Peegee etc

Early spring before

bud break

Flowers on this year’s growth. Do not cut back as hard as arborescens

varieties, but establish a woody framework anything from 10 –36” tall, prune

back previous seasons stems to 2-4 strong buds. Only paniculatas can be

pruned to tree forms by letting one vigorous stem grow upward, cutting it off

at required height and after branches have developed cutting them back to 4

buds. Thereafter prune the top as you would a shrub. Cutting off at the ground

level will revert back to shrub form.

Hydrangea macrophylla –

Twist-n-shout etc.

For Wisconsin

.

Late summer after

flowering

Early spring

Flowers on new and previous year’s wood. Cut back dead flower heads to a

strong pair of buds or new shoots. On older bushes, cut out some of the thin,

weak or old wood to the ground to keep the shrub vigorous.

For zone 4 it dies back so should be treated like annabella and cut back in

spring

Philadelphus

(Mockorange)

After flowering Flowers on previous year’s wood. On younger plants, only cut vigorous stems

that have flowered to strong side shoots. On mature plants, also cut out a few

woody older branches that no longer bloom to ground level. Don’t need to

prune every year. Best when left to reach full size naturally. Can be completely

cut down for renewal

Physocarpus (Ninebark) Early spring Actually flowers on previous year’s wood but flowers are insignificant so

prune in spring.. On mature plants, cut out older branches to the ground. Don’t

just cut part of the branch, as twiggy shoots will sprout from the end of the

pruned branch.

Potentilla Early spring Flowers on this year’s growth. Cut out a few of the older less flowering stems

and shorten overlong stems each year in spring to renew vigor. Potentillas are

more attractive with a loose open form so don’t just shear them back at this

time. After flowering, trim with shears to tidy up. Doesn’t like to be

completely cut back

Raspberries-fall bearers or

(everbearers)

summerbearers

Late fall

Late fall

Bear fruit on new canes.Cut completely to the ground each year

Bear fruit on previous years canes. The 2-year-old canes that have just finished

bearing and are woody with light green-yellowish leaves should be cut to the

ground. The new green canes with lush green foliage should be thinned out

leaving the thickest canes 3-4 per foot of row, these will bear fruit the

following year. In the spring head these canes back to 5 feet.

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Rhododendron

Azalea

Late spring after

flowering

Generally little pruning is needed. Dead heading flower clusters will encourage

new growth. Pinching out slender terminal growth buds (not the fat flower

buds) will promote branching. Long leggy branches can be cut back to an inch

above a leaf whorl to encourage a more compact growth. Overgrown shrubs

respond well to hard rejuvenation, but will take a few years to bloom again. To

rejuvenate cut back main branches to staggered heights of around 6” best done

during winter dormancy

Little pruning needed. Prune back over long stems to side branches

Salix (Willow)

shrub form

Early spring Thin out oldest stems. To rejuvenate cut completely to the ground.

Varieties with colorful stems should be cut down to 6-12” in a fan shape each

year to encourage new colorful growth

Spirea – Spring flowering

Renaissance, Grefsheim

etc.

Late spring after

flowering

Flowers on previous year’s wood. Cut out some of the oldest stems at the base.

If necessary overlong stems can be cut back but try to maintain graceful

arching effect of branches

Spirea – Summer

flowering

Sp.japonica – Neon Flash

Sp.bumalda - Goldmound

Early spring Flowers on new growth. Thin out oldest stems and shear back hard up to ½ of

the growth. A light trimming after flowering in the summer to clean up can

also be done, which might stimulate a new flush of flowering.

Symphoricarpos

(Snowberry)

Early spring Flowers on new growth. Cut out some of the unproductive older stems to the

ground each year. Don’t just head back these shrubs as much of their beauty

lies in the gracefully arching young branches. Pull out stems that spread too far

to keep a compact base

Syringa (Lilac) Late spring after

flowering

Flowers on previous year’s wood. Deadhead after flowering, overlong

branches can be cut back. As shrubs grow they produce new growth higher up

on increasingly bare limbs which is fine for more of a tree form. To keep it as

shrub remove some of the old stems at the ground each year. Plenty of new

shoots will be produced - thin out the excess weak ones, retaining the

strongest.

Viburnum After flowering Flowers on previous years wood. Little pruning needed. Cut out weak twiggy

growth from the center. Remove oldest unproductive stems to the ground. Can

be cut back hard to rejuvenate.

Weigela Immediate after

flowering (July)

Blooms on previous year’s wood. Cut back flowered stems so a few pairs of

strong side branches are left on each stem. This will normally be about 1/3 of

the stem being cut off. Most of the stems that are more than 2 years old should

be cut to the ground. Leave only those still producing vigorous new shoots.

Retain only the strongest new shoots that emerge at the plant base.

Cut completely to the ground to renew an old ragged plant, many new shoots

will emerge, keep only the best

Evergreens

Abies (Fir)

Picea (Spruce)

Spring Pruning is rarely needed. When done cut back to another branch or stem. Do

not cut back to bare unbranched wood past the needles, New growth will

not be produced. Pruning the tips to a side branch or bud will encourage

growth for more bushiness.

Lower branches should be allowed to drape to the ground, they support the

upper branches when covered in snow.

Firs = flat needles, cannot roll between fingers

Spruce = four sided needles, easily roll between fingers

Pinus (Pine) Spring- mid June No pruning as few side buds are produced. For bushier plants pinch off 1/3 of

the tips of new growth (candles) with fingers (cutting surrounding needles by

using tools will result in brown tips)

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Juniper

Thuja (Arborvitae)

Chamaecyparis

Russian cypress

Anytime but best in

spring

Little pruning needed. New buds are not produced on bare wood, so do not

cut back further than green foliage.

While shearing is quick and easy it creates a dense growth of foliage on the

plants exterior which shades out the interior resulting in a thin shell of foliage

which is more susceptible to browning and winter dieback. It is better, but

more time consuming to cut back to an upward growing side branch

Taxus - Yew Anytime Resprouts from bare wood so tolerates any amount of pruning or shearing,

ideal for hedges. Can be completely cut back to rejuvenate. Left to grow

naturally needs little pruning.

Pinching pine candles Pruning junipe