Proper Pruning of Trees & Shrubs. Jack Kelly Commercial Horticulture Agent University of Arizona Pima County Cooperative Extension

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1 Proper Pruning of Trees & Shrubs Jack Kelly Commercial Horticulture Agent University of Arizona Pima County Cooperative Extension January, /8/2015

2 Damage on Opuntia ficusindica

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9 Freeze Damage Wait until bud break or March 15 th. If you must prune, keep it to a minimum

10 Use the right tool for the job

11 Why Do We Prune Plants? To remove damaged/broken branches

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15 Why Do We Prune Plants? To remove damaged/broken branches To remove rubbing, crossing, inwardly growing branches

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18 Why Do We Prune Plants? To remove damaged/broken branches To remove rubbing, crossing, inwardly growing branches For visibility & safety considerations

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21 Why Do We Prune Plants? To remove damaged/broken branches To remove rubbing, crossing, inwardly growing branches For visibility & safety considerations To train young plants

22 Co-dominant leader

23 Why We Prune Plants (cont d) To remove dead, damaged or diseased branches Always have a good reason to prune

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26 1. On dead branches cut just beyond the live part of branch 2. Only cut off dead portion

27 Live portion Cut here Don t cut here

28 Why We Prune Plants (cont d) To remove dead, damaged or diseased branches Rejuvenation of plants

29 Rejuvenation of Caesalpinia pulcherrima

30 Why We Prune Plants (cont d) To remove dead, damaged or diseased branches Rejuvenation of plants Increase flowering, fruiting and vigor Always have a good reason to prune

31 Branch Collar Always look for the branch collar before making any final cut

32 Branch Collar

33 Branch Collar Branch Bark Ridge Branch Collar and Branch Bark Ridge

34 Branch Collar Branch Bark Ridge

35 Branch Bark Collar

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37 Don t Leave Stubs The stubbed stem will die back into the trunk of the tree and act as an entry for wood-decaying organisms

38 Branch Collar Callus Stubs

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44 The Three Cut Method of Removing Large Branches 1. Make an undercut 12 inches from trunk and 1/4 through branch

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46 First Cut

47 The Three Cut Method of Removing Large Branches 1. Make an undercut 12 inches from trunk and 1/4 through branch 2. Make second cut within 1 inch of the undercut (away from first cut)

48 First Cut Second Cut

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50 The Three Cut Method of Removing Large Branches 1. Make an undercut 12 inches from trunk and 1/4 through branch 2. Make second cut within 1 inch of the undercut (away from first cut) 3. Remove branch just beyond the shoulder and the branch bark ridge

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52 Branch Bark Ridge

53 Pruning Young or Newly Planted Trees Remove only dead, damaged, diseased, rubbing or inwardly growing branches

54 Pruning Young or Newly Planted Trees Remove only dead, damaged, diseased, rubbing or inwardly growing branches Leave thin side shoots on the trunk and trim back to about 4-6 inches

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56 Pruning Young or Newly Planted Trees Remove only dead, damaged, diseased, rubbing or inwardly growing branches Leave thin side shoots on the trunk and trim back to about 4-6 inches Don t elevate the crown on newly planted trees drastically

57 Crown excessively raised (L) and weak branch angle (R)

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59 VERY IMPORTANT! Visualize what the plant will look like with the branch removed Remove no more than 15-20% of the old branches annually

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61 Flush Cut

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67 What is Included Bark? Included bark is bark that gets enclosed in the crotch of a tree as the branches and trunks develop. Think of it as pinched bark

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69 Area of included bark

70 Why Does Included Bark Cause Problems? 1. It weakens the branch attachment 2. The tree is more prone to storm damage

71 Included bark

72 Included bark

73 What s Wrong with Topping Trees? 1. It is a source of invasion by rotcausing organisms

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75 What s Wrong with Topping Trees? 1. It is a source of invasion by rot-causing organisms 2. It reduces the food- manufacturing capacity of trees

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78 3. New limbs that originate near the cuts are weakly attached and break easily in the wind. A re-grown limb never has the structural integrity of the original limb.

79 Original trunk This branch was topped and the new growth is poorly attached to the original limb Note parallel grain and lack of branch collar Trunk beginning to rot

80 4. Thick re-growth of suckers or sprouts has greater wind resistance leading to more storm and wind damage. 5. Topping does not help in keeping a tree smaller or lower in height

81 Re-growth one year after topping

82 6. It s expensive to have the tree retopped every few years due to rapid, thick re-growth of branches. 7. It s ugly! The re-growth of a mass of straight suckers and shoots.

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85 8. It makes you and your employer look bad. Informed people know that topping is not an accepted procedure

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87 Topping does not reduce the size of the tree. Regrowth as a result of the topping encourages rapid, weaklyattached new growth

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90 Point of topping

91 Drop crotch pruning offers an alternative to topping

92 How to Prune a Tree 1. For new plantings, wait a full growing season before fertilizing or pruning 2. Always use clean, sharp tools 3. Only prune if you have a good reason to prune

93 4. Leave the low, side branches on young trees 5. Don t over-prune either the crown or branches 6. Don t use tree wound dressing or paint

94 7. Prune to eliminate weak growth or poor branch locations 8. Prune just outside the branch collar 9. Prune to open the canopy 10. NEVER TOP A TREE 11. NEVER LION TAIL a trunk or branch

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96 How to Prune Shrubs

97 If the plant must be drastically reduced in size, reduce it over a 3-4 year period Make cuts on shrubs at varying lengths in order to leave the shrub with a textured natural look

98 VERY IMPORTANT! Visualize what the plant will look like with the branch in question removed Remove about 25-30% of the old branches annually

99 Hedges

100 Hedges Choose evergreen plants with small leaves, short internodes, dense branching and that are able to sprout from old wood Keep the number of hedges to a minimum because they are labor intensive

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104 How to Rejuvenate Large Shrubs 1. Cut shrubs to12-18 inches above ground 2. The stumps will re-sprout in several months 3. Thin out the number of shoots the second year and reduce the overall height by half

105 4. The result will be a full, vigorous, rejuvenated shrub 5. Not all species respond positively to this treatment This technique does not work with all shrubs. Typically fast growing plants respond to this radical pruning

106 Fast growing plants such as Texas Rangers, Jasmine, Oleander, Acacia redolens, etc can be pruned to within inches of the ground and will re-sprout rapidly

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110 The Bad and the Ugly

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125 Branch Collar Callus Stubs

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127 Thank You QUESTIONS?

128 Issued in furtherance of Cooperative Extension work, acts of May 8 and June 30, 1914 in cooperation with the U.S. Department of Agriculture, James A. Christenson, Director, Cooperative Extension, College of Agriculture & Life Sciences, The University of Arizona. The University of Arizona is an equal opportunity, affirmative action institution. The University does not discriminate on the basis of race, color, religion, sex, national origin, age, disability, veteran status, or sexual orientation in its programs and activities. Persons with a disability may request a reasonable accommodation, such as a sign language interpreter, by contacting DRC (Disability Resource Center) at (V/TTY). Requests should be made as early as possible to allow time to arrange the accommodation.