Post on 03-Mar-2017
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All Things Pruning…
JayDee GunnellAssociate Professor
Salt Lake County Extension
Utah State University
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The Four W’s
When is the best time?
Why do we prune?
What do we prune off?
Where do we make the cuts?
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What to use…
Saw – 2”+ large branches
Hand Pruners – ½”-1” branches
Loppers – 1 ½” branches
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When to Prune?-Trees & Shrubs-
Winter or early spring is best
-Easy to see the form
-Plants are dormant
Shrubs that bloom before June 1st
-Prune after bloom
Forsythia, Lilac, Mock Orange
General rule of thumb:
You can prune in any month that doesn’t end in “R”
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Pruning Shrubs
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Prune Anytime…D-D-D
• Dead
• Broken
• Diseased
• Hanging
• Crossing / Rubbing
• Water-sprouts
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Pruning Language
• Telling a plant where to go.
What language are you using?
*@?!!#*!!!
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Nodes and Internodes
-Nodes - points where buds, leaves or twigs attach to stems
-Internodes - stem portions between nodes
Internode
Nodes
Internode Internode
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Working with Nature
• Apical Dominance…
Suppressing hormones produced by terminal buds-Terminal bud (king)
-Lateral buds (simpletons)
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Two Basic Pruning Cuts
1- Heading cuts
-“Iffy” language
-Done at internodes
-Forces lateral growth
-Topping (hat-racking)
-Sheering
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Topping / Hat-racking
Very damaging-Causes:
-Water sprouts
-Weak angles
-Decay
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Don’t Leave Stubs!
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Two Basic Pruning Cuts
2- Thinning cuts
-“Nicer” language
-At the node
-Total branch removal
-drop crotch
-directional pruning
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Natural Target Pruning
Correct
IncorrectBranch Bark Ridge
Branch Collar
Correct
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Natural Target Pruning
Branch Collar
Branch BarkRidge
Branch Removal
Top Removal(Drop Crotching)
Good Pruning Cuts
Bottom of Cut Straight Across
from BBR
-Leave branch bark ridge-Leave branch collar-No stubs-No flush cuts
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Natural Target Pruning
Branch Collar
Branch BarkRidge
Branch Removal
Bottom of Cut Straight Across
from BBR
Top Removal(Drop Crotching)
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Pruning “Donuts”
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Pruning Don’ts
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Renewal Pruning-Large Shrubs-
• Increases new growth
• Remove 1/3 of the oldest canes– (to the ground)
• Reduce the length of branches– (no sheering)
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Rejuvenation Pruning-Large Shrubs-
• Neglected shrubs
• Cut shrub to the ground– extreme pruning
– may not grow back
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Pruning Evergreens
• Plant the right one!• Dead /Diseased /Broken• Three types of evergreens:
– Whorl-branched• Pine, spruce, fir• Only 1/3 of new candle
– Random-branched• Juniper, arborvitae, yew• Tolerate sheering
– Broad-leaf• Boxwood, Euonymus • Tolerate sheering
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Roses
• Most popular flowering shrub.
• All colors available (not black, true blue)
• Diversity– Size
– Shape
– Color
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Pruning Roses
• Pruning renews growth.• Pruning promotes blooms.• Prune ¼” above an
outside-facing bud.• Seal cuts with glue.• Timing depends on the
type of rose…
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Hybrid T’s, Floribunda, Grandiflora & Miniatures
• Produce blooms on current seasons growth
• Need annual pruning
• Mid-April when buds swell
• Leave 3-5 canes, 12-18”
• Dead-heading –removing spent flowers, cut to the 1st 5 leaflet.
Floribundas and miniatures don’t need to be pruned as heavily as Hybrid T’s.
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Climbing Roses• Leave alone for 2-3 years.
• Bloom on 1 year old wood
• Most are repeat bloomers.
• Prune early spring.
• Prune to fit trellis
• Leave 4-6 eye buds per lateral
• Only leave canes for 3 years.
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Rambler Roses
• Bloom on 2 year old wood
• Bloom one time per season
• Prune after they bloom (early summer)
• Leave 5-7 canes (un-pruned)
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Questions?
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General Requirements – Fruit treesSoil
-drainage (air & water)Water
-deep, infrequent watering.Fertilizer
-none at planting-generally only nitrogen is needed:
2-3 years old – ½ lb.4-8 years old – 1 lb.Mature trees – 2–3 lbs.
-at least 1 month before bloom time -according to shoot growth (best indicator)
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Average Shoot Growth
Fruit Tree
Average Shoot Growth (in inches)
Young Trees (1-6yrs) Older Trees (over 6 yrs)
Apple, Dwarf & Semi-Dwarf 10-20" 4-8"
Apple, Standard & Spur-type 10-20" 6-10"
Peach, Nectarine & Apricot 10-24" 8-15"
Sour Cherry & Plum 10-20" 8-12"
*Pears do well with little to no fertilizer
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Fruit Pollination• Apples
Need cross pollination – similar bloom time• Pears
Need cross pollination • Cherries
Need cross pollination (Stella self-fruitful)• Plums
Vary greatly in pollination requirements• Peaches
Self-fruitful (except Hales)• Apricot
Self-fruitful
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Apple Pollination Chart
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Anatomy & Vocabulary
• Graft union– Scion
– Rootstock
• Leader
• Suckers
• Water sprouts
• Spurs
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ScionFruiting cultivar
Rootstock
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Why
To produce high quality fruit-Maximum solar exposure
To maintain fruiting wood-Reduce shading from interior
To tell a tree where to grow!
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When
-During the dormant season
-After the coldest part of winter
-Late February – bud swell
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Where to cut…
Heading cuts• shortening a branch or shoot
• encourages lateral growth
Thinning cuts• remove entire branch or shoot back to a lateral branch or
trunk
• directs growth
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Pruning…as simple as 1,2,3
1- Clean up the dumb branches first-broken / diseased-rubbing -hangers-suckers -water-sprouts (early summer when 2-4”)
2- Know where the fruit grows
3- Let the light intraining systems
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Peaches
• Fruit on last years wood.
• 3 mixed buds
2 fruit buds
1 leaf bud
• Heavy annual pruning (50%)
Generally 12” shoot can produce 2 peaches
• Apricots, cherries and plums produce fruit anywhere.
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Delayed Open Vase(Peaches, Apricots, Nectarines, Japanese plums, Sour cherries)
• Select 3-4 primary scaffold branches
-45-60 degrees
-About 18-24” from the ground
-Evenly distributed in a whorl.
-6-8” apart vertically
• Remove any growth 6” from the trunk
• Allow 2 secondary scaffolds to form when primary scaffold are 4 feet long.
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Peach Tree - Before
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Peach Tree - After
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Apples & Pears
• Fruit on spurs that are 2-5 years old.
• Buds differentiate (mid June)-Alternating years
• Prune lighter once primary scaffolds are formed.
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Fruit Thinning – Why?
• Produces better quality fruit• Promotes annual bearing
– late May – Early June– after “June drop”– fruit = pea – dime size
1 peach every 5-6”1 apple every 5-6”
(every 2-4 spurs)
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• Select 4-5 primary scaffold branches-About 24-36” from the ground-Evenly distributed in a whorl.-4-6” apart vertically
• Head the terminal above where the 2nd scaffold will be.
• Select 3-4 primary scaffold branches-About 24” from the first whorl-4-6” apart vertically
• More horizontal branches control vigor.
• 45-60 degree angles are optimal
Modified Central Leader(Apples, European plums, Sweet cherries, Pears)
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Pruning Unruly Trees
• Decision Time…
1 cut at ground level?
• Never prune more than 1/3 of the tree at one time.
• Don’t fertilize the tree during corrective pruning
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Berries
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Pruning GrapesFour-cane Kniffin System
Fruit is found on shoots growing from year old canes.
One main trunk trained to a 2 wire trellis system (24-30” apart)
4 canes (year old) – 10-15 buds on each cane or 40-60 per plant
• Each bud will form 2-3 grape clusters
Renewal spurs– 4 renewal spurs with 2 buds
– Next year’s fruiting wood
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Pruning Tips-Select canes that are 1/4” in diameter
– Avoid weak & “bull” canes
-Mark or tape the 4 “keepers” and tie them to wire first.
-Remove everything else!– (Except the renewal spurs)
*Correct pruning = removing 80-90% of the grape plant
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Pruning Raspberries
• Perennial roots
• Biennial canes– 1st year canes – primocanes
– 2nd year canes – floricanes
• Spread by suckering
• Two types of raspberries:• Summer-bearing
• Fall-bearing (ever-bearing)
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2 types of raspberries
Summer-bearingday-length sensitiveset flowers in fall, produce fruit next June /Julyfruit on floricanesthen they die
Fall-bearing (ever-bearing)not day-length sensitivefruit on primocanes (first fall, on the tips)fruit on floricanes (next summer, lower on cane)then they die
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Pruning Summer-bearing Raspberries
Produce one crop in June/July
-Early spring (March-April)
-Remove dead / weak canes (winter damage)
-Thin healthy canes to 6” apart
-Remove spent canes after harvest
-Rotation between primocanes & floricanes
-Typically need support or trellised
extension.usu.edu*http://www.inberry.com/
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Pruning Ever-bearing Raspberries
Two options
1- Produce 2 small crops June & August
2- Produce 1 large crop in August
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Pruning Ever-bearing Raspberries
Two small crops (June & August)
-Early spring (March-April)-Remove dead / weak canes (winter damage) -Thin healthy canes to 6” apart
-Prune canes to 4-5’ (below fruited section) -Remove spent canes after harvest-Rotation between primocanes & floricanes
extension.usu.edu*http://www.inberry.com/
Ever
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Pruning Ever-bearing Raspberries
One large crop (August)
-Early spring (March-April)
-Mow everything down to 2-4”
-That’s it!!
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Pruning Blackberries
• Perennial crowns
• Biennial canes
• Don’t sucker like raspberries• Planted in a hill system
• Two basic types:• Erect / semi-erect
• Trailing
• Stems can be either…• thorny
• thornless
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Pruning Blackberries
• Canes cut back to 5-6 feet (mid summer)– Helps stiffen canes
– Induces lateral branching
– Laterals shortened to 12-16 inches
– Long laterals produce many small fruit
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http://utahpests.usu.edu
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Questions?
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The Top 5 Fruit Problems
1- Codling Moth
2- Peachtree Borer
3- Western Cherry Fruit Fly
4- Fire Blight
5- Coryneum Blight
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The Degree Day Model
• DD - Daily minimum and maximum temperatures
– March 1st – start counting
• Biofix – when adults are caught consistently
– Start counting over
• Utah accumulates 2,500-3,500 DD per season
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Codling MothDescription:
- overwinter as pupae on bark- adult moth with bronze band
- active at 55-60 degrees F.- usually at bloom- 3 weeks to mature, mate, lay eggs
- eggs are laid on leaves and fruit- larvae tunnel into fruit to feed on seeds
- 2-3 generations per year
Hosts: - apples- pears
Remedies: - Target eggs or emerging larvae- Traditional chemicals:
Malathion – every 5-7 daysCarbaryl (Sevin) – every 7 days
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“Softer” SolutionsCultural control:
pick up dropped fruit (June drop)thin apples to every 5-6”
Trunk banding: place corrugated cardboard bands (3-4” wide) around trunks from June-Sept.
Fruit bagging: apple bags placed on individual fruit (May-Aug)
Alternative Solutions:Spinosad (Entrust) - every 3-10 daysBt (Dipel, Crymax, Javelin) - every 3-5 daysPyrethrin (Pyganic) – every 5-7 daysHorticultural Oil – no more than 3-4 applicationsCodling Moth Virus (CydX, Virusoft) - every 7 days
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Peach Tree BorerDescription:
- overwinter in soil near trunk- adult clear-winged moth- exit holes with sawdust and gum (1’ from soil line)
Hosts: - peaches, nectarine, apricot, cherry, plum
Remedies: - Mating disruption (more than 1 acre)
- Protective spray from July 1st – early September(only lower trunk and crown)
- Traditional chemicals:MalathionCarbaryl (Sevin) Permethrin
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Western Cherry Fruit FlyDescription:
- overwinter in soil as pupae- adults emerge late May early June
- small fly lays eggs under skin of fruit- fruit must have salmon blush
- larvae (maggots) develop inside fruit- only 1 generation per year
Hosts: - sweet and tart cherries
Remedies: - Target adult flies- Traditional chemicals:
Malathion – every 3-5 daysCarbaryl (Sevin) – every 5-7 days
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“Softer” SolutionsCultural control:
- weed barrier under trees to eliminate pupae burrowing
- sanitation of orchard floor
Sanitation: keep fruit picked up as it falls
Alternative Solutions:Spinosad - every 7 daysGF-120 – attract n’ kill every 7 days
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Fire BlightSymptoms:
- Common on apple and pear
- Scorched appearance on leaves, blossoms, and shoots
- Shepherd’s crook on terminal growth
- Bacterial oozing may be present
- Dark and sunken areas in the bark
Cause: - Bacteria: Erwinia amylovora
- active during warm, wet springs
- spread to blooms by pollinators and splashing rains
- enters primarily through blossoms
Remedies: - Prune out infected wood 8-12” below visual damage
(Only during dry weather)
- Remove pruned wood to avoid spreading
- Preventative bactericide during bloom extension.usu.edu
Coryneum BlightSymptoms:
- Common on peach, apricot, cherry, plum
- Small round lesions
- Girdling cankers on twigs
- Gumming may be present
Causes:- Fungus – Wilsonmyces carpophilus
- prominent during cool, wet springs
Remedies: - Prune out infected limbs
- Apply registered fungicides:
- fall @ 50% leaf drop
- spring at shuck split
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stem canker