Pruning Woody Plants

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Pruning Woody Plants
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Maintenance of Woody Plants

• Pruning Formative, maintenance and
• renewal
• Mulching
• Deadheading
• Watering
• Weeding
• Staking
• Feeding

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Pruning Woody Plants

• Why Prune????
• To make sure plants dont get too big
• To remove dead, dying, damaged or diseased wood.
• To train or shape e.g. espaliers, topiary, hedges
  etc.
• To maintain or improve flowering and fruiting
• To encourage fresh re-growth

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Pruning Responses

• Pruning reduces the size of the aerial portion of
  the plant in relation to the root system.
• The undisturbed root system therefore serves
  fewer shoots and buds.
• Uptake of water and nutrients by the remaining
  shoots and buds therefore increases and a flush
  of growth (re-growth) occurs.

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Water Sprouts/Shoots
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Pruning Responses

• Pruning generally stimulates re-growth near the
  cut especially in vertical limbs that have been
  pruned
• Re-growth on limbs having a 45 to 60 degree angle
  from the vertical will develop further away from
  the cut

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Pruning Responses

• Pruning also may indirectly stimulate growth of
  lateral shoots by allowing more light to
  penetrate the canopy of the plant
• Pruning a young plant will stimulate vigorous
  shoot growth but can delay the development of
  flowers and fruit
• The length of any delay depends on the species
  pruned and the severity of the pruning

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Pruning Cuts

• Above a bud in the case of small branches
• Should always be cleanly done
• Well below infected material e.g. bacterial
  canker
• Aim to minimise the surface area
• Always avoid tearing
• Dont apply wound dressing

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Types of Pruning Cuts

• There are two basic types of pruning cuts
• Heading removal of a part of a shoot or
• limb
• Thinning removal of the entire shoot or
• limb
• Each results in a different growth response and
  has its own specific uses

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Thinning

• Removes an entire shoot or limb to its point of
  origin from the main branch or lateral
• Some shoot tips are left undistributed, so apical
  dominance is maintained

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Thinning

• New growth occurs at the undisturbed shoot tips
  while lateral bud development and re-growth is
  suppressed
• Thinning is the least invigorating type of
  pruning cut and provides a more natural growth
  form

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Thinning
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Heading

• By removing apical dominance, heading stimulates
  re-growth near the cut
• It is the most invigorating type of pruning cut,
  resulting in thick compact growth and a loss of
  natural form e.g. a formally pruned hedge
• Other types of heading are topping, pollarding
  and clipping

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Heading
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Which is Heading and Which is Thinning???
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Wound Dressing

• Traditionally bitumastic emulsions used
• Drying, movement of woody tissue and water build
  up all cause micro-fractures to seal
• These cracks are the ideal place for fungal or
  bacterial spores to germinate
• Humid, sheltered, next to a food source
• May actually increase chances of decay
• Innoculants such as Trichoderma viridae can
  reduce incidence of disease

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Angled or Straight Cuts

• All cuts should aim to minimize size of wound
• Angled cuts leave an oval scar that may increase
  chances of disease entry
• Angled cuts may be useful however above
  alternately arranged buds, especially where buds
  are large
• Angled cuts must never fall behind the node itself

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Angled or Straight Cuts
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Timing of Pruning

• May be crucial in certain species
• Variable. Depends upon
• Growth pattern
• Effect desired
• Tolerance of subject
• May need to be done more than once a year (i.e.
  in stages)
• May only need doing every few years

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Timing of Pruning

• Avoid heavy pruning during the late summer and
  autumn as vigorous re-growth may occur making the
  plants more susceptible to cold injury
• Peach and almond trees for example, should not be
  pruned from October until January

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Hard or Light Pruning

• Hard Pruning
• Promotes rapid, vigorous re-growth in some
  specimens this is the best form of management
• May be undesirable in the case of some vigorous
  specimens Re-growth greater than existing
  growth (space considerations)
• May promote suckering or epicormic growth

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Hard or Light Pruning

• Light Pruning
• Suits specimens intolerant of hard pruning e.g.
  Lavandula as it does not re-sprout very
  successfully
• May also be suitable to prevent excessive shock
  response
• As a rule of thumb
• Prune weak growth hard and strong growth lightly
  if unsure of the plants needs

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Timing of Pruning

• Many woody ornamentals are pruned according to
  their date of flowering
• E.g. spring flowering plants such as forsythia
• are normally pruned after they bloom
• Prune spring flowering shrubs during the dormant
  season will remove flower buds formed the
  previous autumn
• Summer flowering plants are generally pruned
  during the dormant winter season

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Bleeding

• Some plants bleed heavily after pruning
• Bleeding is unsightly but not usually harmful
• Trees prone to bleeding should be pruned in the
  late spring or early summer when leaves are on
  the tree as this reduces the amount of bleeding
  and allows rapid healing
• Plants that bleed readily include Salix, Betula,
  Acer, Fagus and Cornus

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Aftercare

• Shrubs that have been pruned often need
  considerable amounts of soil borne nutrients to
  resume normal growth
• Application of a topdressing of fertilizer is
  essential
• Well rotted organic matter applied as a mulch
  can further enhance the soil fertility and
  promote growth

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Scaffold Establishment for a Freestanding Tree

• Scaffold branches of trees should have a proper
  vertical and radial spacing on the trunk in order
  to allow a balanced growth pattern

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Training

• Growth of lower buds or shoots can be modified by
  training
• Upright stems often suppress the development of
  lower side shoots
• Training stems horizontally can greatly increase
  both the growth rate and development of
  flower/fruit carried
• Stems must be tied in when young and pliable

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Formative Pruning

• Aims to establish a framework of well formed and
  well placed branches (often referred to as a
  scaffold)
• Amount needed depends upon
• Type of plant concerned
• Quality of initial plant
• The growth stage
• Evergreen shrubs generally need less formative
  work

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Root Pruning

• May be needed when vigour of a plant needs
  controlling
• Bonsai, pot grown trees or shrubs etc
• May be an essential part of the prior preparation
  for lifting root-balled shrubs or trees
• Trenching and backfilling
• May be done on bare rooted stock immediately
  prior to replanting

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Renovation

• Old unmanaged specimens can be renovated through
  pruning
• Check tolerance to hard pruning before commencing
• Usually best practiced over a 2-3 year cycle
• Not worth attempting on badly diseased specimens

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Renovation

• Deciduous shrubs should be renovated in the
  dormant (winter) period
• Delay work on evergreens until growth commences
  (March/April)
• Certain tolerant species can be coppiced
• Cut back to a stump or stool near ground level
• Always feed and fertilize well in the following
  season
• Undertake formative pruning as a follow up

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Choose your weapon

• There are many different types of pruning tools
• They have specific purposes
• Always choose the right tool for the job and
• .Never try to work beyond the capacity of the
  tool whilst in use. It will make the job harder!

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Get a Grip

• Hold secateurs properly i.e. comfortably in the
  hand
• Make sure the anvil is positioned on the part to
  be removed
• Cutting should be in one easy motion..
• .if it squeaks to a stop then use a bigger or
  more appropriate tool!

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Make a Plan!

• Always ask yourself
• What plant species is it?
• What are its pruning requirements?
• What effect will pruning have on its growth?
• Do I have the right tool(s) for the job?
• What are my objectives in undertaking this task?

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In Conclusion

• Always look and think twice before cutting if
  unsure. Once you make a cut there is no going
  back!

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A Final Word

• Always remember the Ds when you prune
• Always remove them when you prune any shrub
• Dead
• Dying
• Diseased
• Deformed
• Displaced

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Sources of Information

• Brackell, C. and Joyce, D. (1996) The Royal
  Horticultural Society, Pruning Training A
  fully illustrated plant by plant Manual. Dorling
  Kindersley, London.
• Davis, B. (1995) The Confident Gardener The key
  to successful gardening techniques. Penguin,
  London.