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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