Pruningshrubs Part 1
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Pruning shrubs depends on their flowering habit and growth habit. For flowering shrubs, pruning timing is based on whether the shrub blooms on old or new wood. Cane-growing shrubs regenerate from the base, while permanent framework and subshrubs have a woody structure and regenerate from the top. Proper pruning enhances the plant and removes dead or damaged parts.
Pruningshrubs Part 1
- 1. Pruning Ornamental Shrubs and Vines By Neil Bell Community Horticulturist Marion and Polk Counties
- 2. Contents: What is pruning? Why prune? Timing of pruning Frequency of pruning Pruning principles Pruning references Specific pruning techniques: Shrubs Conifers Vines
- 3. What is Pruning? The selective removal of specific parts of the plant to benefit the whole plant Pruning is NOT: a way to compensate for inappropriate plant placement!
- 4. Plant placement Consider the mature size of plants and available space before you plant!
- 5. Why Prune? Remove dead, diseased or broken parts Prune out winter injury
- 6. sucker removal
- 7. Enhance a characteristic-coppicing From the French “to cut” used to enhance leaf, stem effect Shrub dogwood
- 8. Coppicing to enhance leaf size… Cotinus coggygria (smokebush)
- 10. Develop unusual forms espalier, bonsai topiary
- 11. Train a young plant Rosa mulliganii (Before) Later…
- 12. Stimulate new wood thinning rejuvenation
- 13. Size Control short term only!
- 14. Why Prune at all? Pruning is a stress on plants March June
- 15. Plant will grow unassisted to natural form is that really desirable? Holodiscus discolor (Oceanspray)
- 16. Timing of Pruning Depends on: 1. Flowering habit Blossoms on old wood Blossoms on new wood Viburnum plicatum Phygelius
- 17. 2. Objectives remove dead wood anytime 3. Rate of healing quickest response is just prior to beginning of new growth
- 18. 4. Risk of suckers greatest in e. spring less problem in summer Malus, Syringa 5. Risk of winter injury Rosa, Hebe, Salvia etc.
- 19. Frequency of Pruning 1. Prune only as needed know what you want to achieve 2. Age of plant Young plants
- 20. 3. Type of plant clipped hedges 4. Need for size control maybe not practical!
- 21. Most importantly: know what the pruning will do!
- 22. Know the plant and keep a good reference around… don‟t obsess about “rules” observe growth/flowering observe the response
- 23. Principles of Pruning Growth of woody plants Directing growth Principal pruning cuts Adaptations to damage and disease
- 24. Growth habit of woody Plants 2010 Lilac: Syringa vulgaris Spring 2011 2009 2008 Largest buds at branch tips 2007 Not all buds develop twig diameter increases with age 2006
- 25. color change in wood Ribes sanguineum
- 26. Parts of a branch Terminal Bud (auxin) Axillary Bud Node Flower Bud Latent Bud
- 27. Directing growth: Cutting above a bud 450 angle Too angular Too low Too high Good! Alternate-budded plants Opposite
- 28. Response to pruning removal of material causes growth elsewhere removing terminal bud allows lateral development topmost remaining bud grows most strongly alternate opposite
- 30. Another way to force branching…
- 31. Cutting back branches Cut back always to a part that will continue to grow At least ½ the size of the part being removed
- 32. Positioning shears and making a cut avoid leaving stubs use the correct size tool
- 33. Pruning cuts
- 34. Thinning removal of entire stem or section of stem opens up the plant to admit light reduces overall height and promotes regrowth
- 35. Heading (selective) Cutting back to a bud or shoot Promotes branching, will “fill in” the plant
- 36. Shearing Non-selective heading: dense growth at branch tips Unnatural form, appropriate for formal hedges
- 40. Pinching Specializedtechnique for succulent tissues Thinning Promotes branching Heading Pinching
- 41. Renovation Cutting all canes back to near base to renew all growth Very harsh technique: not appropriate for all plants!
- 42. February, 2009 April, 2009
- 43. January, 2010
- 44. Adaptations to damage and disease Plants have no “wound healing” process: healing in a sense of replacing or repairing injured tissues. Plants seal off damaged tissue rather than heal it.
- 45. CODIT Compartmentalization Of Decay In Trees Plants are highly ordered, compartmented Instead of healing, plants compartmentalize injured and infected tissues.
- 46. callus tissue is produced on the wound margin
- 47. Wound paints and dressings evidence for use is inconclusive no given treatment fulfills all requirements 1. Prevent decay 2. Speed wound closure 3. Inhibit insect or diseases
- 48. Pruning Shrubs When and how to prune a shrub depends on… 1. Flowering habit 2. Growth habit Calycanthus x raulstonii Salix caprea var. pendula
- 49. Determining time to prune flowering shrubs The “flowering habit” 1. Blooms on “old” wood: after flowering 2. Blooms on “new” wood: early spring The issue is: When does the shrub form the flower buds?
- 51. Distinguishing between “old” and “new” wood Spring blooming shrubs develop buds in fall Tend to bloom early in season Summer/fall blooming shrubs form buds as they grow Tend to bloom later in season Chaenomeles-spring bloom Spiraea x bumalda -summer bloom
- 52. Length of bloom period Spring bloomers: 2 weeks? Summer bloomers: often more than a month Rhododendron Fuchsia magellanica
- 53. Flower type: terminal or axillary Crabapple (Malus)-winter Hydrangea paniculata-winter
- 54. “New” wood versus “old” wood Terminal flowers: Current season wood i.e. Buddleja (July-September) Lateral flowers: One year-old wood i.e Chaenomeles (February-May)
- 55. Distinguishing between “New” wood and “old” wood Flowering time: spring or summer Length of flowering period Axillary or terminal flowers Some shrubs cause confusion! (i.e Hydrangea macrophylla)
- 56. Genera with species that flower on both new and old wood New: Repeat bloomers Rosa Old: Once-blooming, species New: H. paniculata, H. arborescens Hydrangea Old: H. macrophylla New: S. japonica, S. „Bumalda‟ Spiraea Old:S. x vanhouttei, S. „Arguta‟
- 57. How to prune: depends on growth habit Cane growers: Permanent f‟mwork: i.e. Forsythia i.e. Rhododendron usually deciduous Subshrub: EG or deciduous i.e Perovskia EG or deciduous
- 58. Cane growers are easy to identify Hydrangea macrophylla Philadelphus
- 60. “Cane” growers Deutzia Forsythia Hydrangea (lacecap/mophead) Kolkwitzia (Beautybush) Philadelphus (Mock orange) Physocarpus (Ninebark) Sambucus (Elderberry) Spiraea (Bridal Wreath) Rosa (Rose) Viburnum
- 62. Permanent framework Have a “tree-like” structure Do not renew themselves from the base Often are evergreen shrubs Pieris japonica Rosmarinus officinalis „Arp‟
- 64. Permanent Framework Ceanothus (Wild lilac)) Cistus (Rockrose) Daphne Hamamelis (Witchhazel) Hebe Hibiscus (Rose of Sharon) Ilex (Holly) Lavandula (Lavender) Pieris (Andromeda) Rhododendron (and azalea) Rosmarinus (Rosemary)
- 65. Some are deciduous… Hibiscus syriacus (Rose of Sharon) Hamamelis (witchhazel)
- 66. Subshrubs Have a woody framework Produce flowers on new growth Salvia microphylla Phygelius „Sensation‟
- 67. Some examples of subshrubs Artemisia (Wormwood) Caryopteris (Bluebeard) Ceratostigma (Plumbago) Fuchsia magellanica (etc) Gaura lindheimeri Heptacodium (7 Sons Plant) Hydrangea paniculata Lavatera (Tree mallow) Salvia (Sage) Perovskia (Russian sage) Penstemon Phygelius (Cape Fuchsia) Vitex (Chaste tree) Penstemon spp. Zaushneria (California Fuchsia)
- 68. Pruning Cane growers Remove: • dead • damaged • crossing • twiggy growth Thin oldest canes • 1-2 per year Deutzia „Pride of Rochester‟
- 71. Good growth, but dense at base Remove basal canes Sambucus nigra „Madonna‟
- 72. Crowded at base
- 73. Another example… Basal growth removed Weak canes removed Deutzia „Pride of Rochester‟
- 75. Too dense thin canes Too much thinning avoid topping canes!
- 79. Effects of topping canes (i.e. heading) Viburnum opulus Few flowers!
- 80. February April