Pruning basics - Winter · PDF fileAlthough pruning can be done anytime during dormancy (late...
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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 doesnt stimulate side
2. Heading back (cutting back to buds or between buds, promotes side branching and a
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)
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
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)
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)
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 years 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.
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.
Early Spring before
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 years 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
Early spring Usually doesnt 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 years growth. Dont 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 years flowers.
To renew an old neglected plant cut back to 6-12 , old woody stems should be
cut to ground level.
Late fall after
Little pruning needed. Thin out old stems of interior if it becomes crowed.
Hydrangea arborescens -
Early spring before
Flowers on this years 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
Early spring before
Flowers on this years 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.
Late summer after
Flowers on new and previous years 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
After flowering Flowers on previous years 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. Dont 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 years wood but flowers are insignificant so
prune in spring.. On mature plants, cut out older branches to the ground. Dont
just cut part of the branch, as twiggy shoots will sprout from the end of the
Potentilla Early spring Flowers on this years 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 dont just shear them back at this
time. After flowering, trim with shears to tidy up. Doesnt like to be
completely cut back
Raspberries-fall bearers or
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.
Late spring after
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