Grafting

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Grafting

• Defn connecting 2 pieces of plant tissue to grow
  as one plant
• Terms
• scion upper portion (usu. the shoot system)
• stock lower portion (usu. the root system)
• interstock stem piece between the scion and
  stock
• budding scion is reduced to a bud

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Reasons for grafting/budding

• perpetuating clones that cant be maintained by
  other asexual methods
• obtaining the benefits of a rootstock
• changing cultivars of established plants (usu.
  fruit trees)
• obtaining special plant forms
• repairing damaged parts of trees
• virus indexing

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Growth activity of stock/scion wood

• for some methods, best results are obtained when
  both stock and scion are dormant
• for other methods, stock and/or scion wood needs
  to have slipping bark

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Grafting Methods

• Bench grafting
• Field methods
• Container or field methods
• Repair grafting

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Bench grafting

• Whip-and-tongue graft
• Saddle graft

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Whip-and-tongue grafting

• useful for small (1/4-1/2 in.) material, double
  working (interstocks), root grafting, and bench
  grafting
• splice grafting (the tongue is not made)
• both stock and scion are dormant

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Figure 1 Figure 2A (top), Figure 2B (bottom)

Figure 3A (left), Figure 3B (right)
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Saddle grafting

• useful for machine grafting, bench grafting of
  grape and Rhododendron
• scion and stock should be the same size
• grafting is done when stock and scion are
  dormant, then the completed graft is stored in a
  grafting case until the graft union has healed

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Field methods

• Cleft graft
• Wedge graft
• Bark graft
• Four-flap graft

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Cleft grafting

• useful for topworking fruit trees, crown-grafting
  grapes
• the best time is early spring, before active
  growth
• wedge grafting allows 1 more scion per stock

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Formation of successful graft unions sequence of
events

• lining up of vascular cambia
• the wound healing response
• callus bridge formation
• new cambium formation
• vascular tissue formation

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Bark grafting

• Two types (rind and inlay-bark grafts) differ
  only in prep of stocks bark, which should be
  slipping
• often used in lieu of cleft graft later in the
  season

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Figure 23 Figure 24

Figure 25 Figure 26
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Container or field methods

• Side grafts
• Approach grafts

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Side grafting

• defn (smaller) scion inserted into the side of a
  (larger) stock
• Types
• side-stub nursery trees too large for
  whip-and-tongue, not large enough for cleft
• side-tongue useful for broad- and narrow-leaved
  evergreens (e.g., oriental arbovitae)
• side-veneer useful for small potted plants,
  e.g., upright junipers

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Approach grafting

• two independent plants are grafted together
• after union, the top of the stock and the base of
  the scion are removed
• used when other methods are unsuccessful (e.g.,
  Camellia)
• often done on plants in containers
• three methods spliced-, tongued-, and
  inlay-approach grafting

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Repair grafting

• Inarching
• Bridge grafting

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Inarching

• used for repairing damaged roots of a full-grown
  tree
• seedlings are planted around the tree during the
  dormant season, grafting is done in the spring

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Bridge grafting

• used for repairing a damaged trunk
• early spring (with the bark slipping) is the best
  time
• (dormant) scion wood should be 1/4 to 1/2 in.
  diam.

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Technique Date Use
Bark grafting Mid-April through mid-May Establish a pollinating variety on a limb of a tree or to completely topwork a tree.
Bridge grafting Mid-April through mid-May Repair trees girdled above the ground line.
Cleft grafting Late February and March Establish a pollinating variety on a limb of a tree or to completely topwork a tree. Limbs should be 1 inch or more in diameter.
Inarch grafting Mid-April through mid-May Repair trees girdled at or below the ground line. Also used if a root disease is suspected or feared.
Saw-kerf grafting February and March On peaches, nectarines and plums to completely topwork a tree.
T-budding June through mid-September Propagate actively growing rootstocks in the nursery. May also be used to topwork apple and pear trees up to 3 years old and 1-year-old peach, nectarine and plum trees.
Whip grafting February and early March Propagate 1-year-old rootstocks. May also be used to establish a pollinating limb on a young, established tree.
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Fruit Method Method Method
Fruit Propagation in Nursery Topworking Tree Repair
Apple Whip grafting, June budding or dormant budding T-budding on trees three years old or less, cleft or bark grafting on older trees Bridge or inarch graft
Peach, plum and nectarine June budding or dormant Saw-kerf grafting Not normally done
Pear For propagating seedlings, whip graft, June budding or dormant budding For propagating on quince rootstocks, the interstem piece should be whip grafted and the scion variety June or dormant budded onto the interstem. T-budding on trees 3 years old or less, cleft or bark grafting on older trees Bridge or inarch graft
Persimmon June budding, dormant budding or whip grafting Cleft graft or bark graft Bridge or inarch graft