Winter Damage on Nursery Crops and in the Landscape

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Kansas Nursery and Landscape Association/Missouri Landscape and Nursery Association joint summer meeting. July 9, 2014

Oh, the weather outside was frightful! How many times have you stated that plant decline is the result of environmental factors? Many! First drought and heat, now cold and too much rain (who would have thought?). Diagnosing abiotic issues of landscape plants is an important part of our jobs in the green industry. Learn what to look for and how to talk to you clients about their management options.

Published in: Environment

Winter Damage on Nursery Crops and in the Landscape

  1. 1. Oh, The Weather Outside Was Frightful… Winter Damage KNLA/MLNA Summer Meeting, July 2014 Dr. Cheryl Boyer Ornamental Nursery and Garden Center Specialist
  2. 2. What exactly is low temperature damage? Management for nursery production Management for landscape Talking to clients Outline
  3. 3. 1. Chilling injury • Above freezing temps injury (tropicals, annuals) [Freezing = 32°F, O°C] 1. Frost injury • Occurs at or below freezing temps • Caused by radiation freeze (calm, clear nights where plants lose heat to the atmosphere) 1. Freeze injury • Occurs at or below freezing temps • Caused by advective freeze (cool air mass displacing warmer air) 3 Types of Injury
  4. 4. Ice crystals form in plant tissues • Dehydrates cells • Disrupts membranes Other displays of damage • Frost cracks in wood • Black heart of stems (xylem darkening) • Separation of wood along annual rings (cup shakes) • Bark splitting Roots • In soil—generally okay • Raised beds or containers more vulnerable What happens to the plant?
  5. 5. • Water deficit • Gas injury • Chemical injury • Root disease • Anthracnose • Mechanical injury Look-Alike Disorders
  6. 6. 1. Inspect injured plants carefully • Which parts are damaged? • How extensive? • Symptoms consistent with low temp injury? 1. Check the low temperature tolerance of the species. 2. Check the actual temperatures in the area to see if they exceed the species tolerance. Diagnosis
  7. 7. 4. Did symptoms begin to show immediately or some time after the low temperature period? • Some injuries happen after repeated episodes of low temp exposure. 5. Inspect bark and bud tissues. • Water-soaked or dehydrated? • Dark brown or black? [Foliage might die, but bark and bud tissue may still live] Diagnosis
  8. 8. Management in the Nursery
  9. 9. • Death • Wind burn and desiccation • Frost burn Winter Injury
  10. 10. • Cold, clear sunny days • Leaves lose water faster than roots can take it up • Especially if the substrate/soil is frozen Wind Burn and Desiccation
  11. 11. • Damage to leaves • Defoliation Wind Burn and Desiccation
  12. 12. • Frost forms on leaves • Sun shines • Evergreens • Yellowing • Plants recover Frost burn
  13. 13. • Successful winter survival • Roots are alive • Leaves are healthy with no/little damage • Ready to grow Preparing Plants for Winter
  14. 14. • Substrate EC levels • PourThru • Foliar analysis (?) • Correct deficiencies • Especially K • Reduce fertilizer applications Fertilization
  15. 15. • Too much or too little • Drought • Soggy • Reduce frequency • Rehydrate when irrigate Watering
  16. 16. • Irrigate before a cold period • Wet substrate holds heat longer than dry substrate Watering for Added Winter Protection
  17. 17. • As water freezes releases heat • Start when > 32 F • Must continue until > 32 F • Breakage Irrigation as a winter- protection technique
  18. 18. • Avoid pruning within 6 weeks of average first frost • Stimulates bud break • Wound closure • Fungal diseases Pruning
  19. 19. • Remove shade in the fall • Improves acclimation • Decreases bark splitting • Winter hardiness • Absolute and duration of low temperatures Light and Temperature
  20. 20. Field nurseries Site selection Windbreaks Protection Techniques
  21. 21. • Two dangers • Desiccation • Dry substrate (evergreens) • Need to be able to irrigate • Rootball freezes • Root damage • Low temperature Container Nurseries
  22. 22. • Shoots respond to gravity • Sunscald: trunk & branches Avoid laying plants down
  23. 23. Winter Protection
  24. 24. • Push plants tightly together • Reduce air movement between containers Blocking Technique
  25. 25. Structureless Winter ProtectionStructureless Winter Protection Fabric covers 75% to 80% Shade Cloth Thermal
  26. 26. Secure to the Ground
  27. 27. Can irrigate through covers
  28. 28. Why does icing increase the protective value of structureless winter protection?
  29. 29. • Loose cover • Breakage • Heat buildup Damage
  30. 30. Management in the Landscape
  31. 31. What was the impact of 2012/2013 weather and what Plant Problems will show up in 2014? Some problems will carryover from 2012/2013. Depends on the weather. Adapted from a presentations by: Judy O’Mara, KSU Plant Pathology Stuart Warren, Prof./Head Emeritus KSU HFRR
  32. 32. • Environmental stress • Site Factors • Nutrient deficiency • Chemical injury • Insect damage • Disease What can go Wrong?
  33. 33. At K-State Plant Disease Clinic about half the samples are NOT disease — they have an abiotic issue
  34. 34. Kansas is a Transition State W to East Rainfall gradient Prairie State Few native plants Transition zone Plants from North & South TURF ZONE MAP
  35. 35. Look at the weather for a single year. Look at the weather for multiple years. 2014 – Wet or Dry/Hot? 2013 – Wet or Dry/Hot? 2012 – Wet or Dry/Hot? 2011 – Wet or Dry/Hot? 2010 – Wet or Dry/Hot? 2009 – Wet or Dry/Hot? 2008 – Wet or Dry/Hot?
  36. 36. Key words for 2011-2013 Drought and Heat
  37. 37. Winter 2012 – Cold, Desiccating Winds
  38. 38. Spring 2012 A percentage of Oak, Maple, Ash trees Failed to completely green up in the spring. Winter Drought
  39. 39. Turf Failed to Green Up, spring 2012 Drought
  40. 40. July 2012 - Dry
  41. 41. July 2012 Hi Temps & Desiccating Winds
  42. 42. July 2012 Hi Temps & Dry Weather Damage on many ornamental pears due due heat/drought - Looks similar to fire blight which is spring disease (cool/wet)
  43. 43. July 2012 Hi Temps & Dry Growing Conditions on Maple
  44. 44. July 2012 – Hot & Dry
  45. 45. July 2013 – Hot & Dry - YEW
  46. 46. 2012-2013 Ongoing decline of established boxwood
  47. 47. January 2012 – February 2013 Young trees hard to get established
  48. 48. January 2012 – February 2013 Young trees hard to get established
  49. 49. Cedar are drought tolerant but windbreaks are still crashing across the state
  50. 50. Conditions are better, but we are still under Moderate to severe Drought
  51. 51. What does this mean for 2014/2015? Some of the same, but it depends on the upcoming weather.
  52. 52. Annuals – No problem just start over. Perennials – Trees, shrubs, flowers. They likely sustained some root damage and therefore may display top die back. Recent rains and irrigation will help the recovery process for plants that are not too far gone. (~ >30%) Plants with more root damage may continue to decline as summer heat and drier conditions arrive.
  53. 53. Irrigation is important every year. Know your soil type (sandy? or clay?) If using drip irrigation, run the system: •Check all emitters to make sure they work. •Check the soil moisture depth. •Check the root area to see how much of it received moisture.
  54. 54. Mulch can be a plus. •2-3 inches is good. •More is not better. •Don’t pile up around the trunk. •Know your soil type. •Heavy mulch may not work well with clay soils. •Heavy mulch on clay soils can lead to anaerobic conditions and root damage.
  55. 55. Other Abiotic Problems
  56. 56. Wrong plant, wrong site Poor planting method Weather Excavation/soil disturbance Chemical injury “Other” Bad Practices
  57. 57. Siberian Elms – Ice Storm (2006/2007) Weather
  58. 58. FLOODING
  59. 59. Simeon Wright 07 Mid-Late May - Late Freeze or Early Heat Wave!! Hot & Windy in May cooks the new shoot growth on white pine trees ABRUPT Shift in the weather patterns
  60. 60. Drought Stress Impact 1 – 5 yrs later Drought sensitive plants White/scotch pine Spruce Dogwood Viburnum, yew, euonymus, others
  61. 61. 2014 Winter
  62. 62. Remedies and Talking to Clients
  63. 63. Before you make any permanent decisions (pruning or plant removal), give the plants time to recover. Make SURE the plant is dead or will not be recoverable. Wait
  64. 64. • Adequate water • Avoid fertilizing or pruning in the late summer or fall • Stimulates new growth Avoid Additional Plant Stress
  65. 65. • Check K-State and Missouri resources for recommended plants. • Observe plants that survived a rough winter. Suggest Appropriate Alternatives
  66. 66. Sometimes, the answer is just “Environmental.” Planting new species is an opportunity to try new things and enjoy gardening/landscaping.
  67. 67. •Contact KS County Extension office. •Contact K-State: –Ext. Plant Pathology (785) 532-5810. –Ext. Horticulture (785) 532-6173. –Ext. Entomology (785) 532-5891. Where to Get Help?
  68. 68. Plant Problem ID Plant Disease Diagnostic Lab Kansas State University 4032 Throckmorton Hall Manhattan KS 66506 785-532-5810 Judy O’Mara jomara@ksu.edu
  69. 69. Questions? crboyer@ksu.edu Dr. Cheryl Boyer Associate Professor and Extension Specialist Nurseries and Garden Centers

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