1. Diagnosis of Common Woody Landscape Problems
Dr. William M. Fountain
University of Kentucky
Department of Horticulture
Ver 1.0 © 2016
William M. Fountain 37

2. Objectives of Presentation:
Assist you in the understanding of the diagnostic process.
Look at a few common problems (I see) associated with woody landscape plants.
Consider the relationship between different stressing agents.

3. Diagnosis
The systematic approach to discovering the cause(s) of biotic and abiotic disorders.
Prognosis without
diagnosis is
malpractice.

4. Diagnosis
The systematic approach to discovering the cause(s) of biotic and abiotic disorders.
We ask:
▪ What does the normal
plant look like?
▪ Discover the site
history for the plant.
Prognosis without
diagnosis is
malpractice.

5. Diagnosis Understand the concept of Key Plant – Key Pest
▪ Every species is prone
to specific problems.
▪ Diseases and insect pests
are usually host specific.
▪ Monotypic species have
fewer problems
Prognosis without
diagnosis is
malpractice.

6. Diagnosis Digital Images ▪ in focus & large enough!
▪ what is it? (or what do you
think it is?)
▪ whole leaf & plant
(+ buds, fruit, flowers,
& bark)
▪ what is the site like?
▪ what could have happened?
“Client wants to know
what is wrong with
their plant.”

7. Risk Assessment “Never” done via images ▪ too much that cannot
be seen or detected.
I do not compete with private sector.
Always glad to teach y’all (plural you) the process in the field (1 day).
ISA Tree Risk Assessment
Qualification (TRAQ)

8. Risk Assessment Unanswered questions: ▪ size of canopy (& wind)
▪ species
▪ vigor & vitality
▪ target(s) (value & occupancy)
▪ amount of sound wood
▪ response growth
▪ soil characteristics
▪ client’s tolerance for risk

9. Common Landscape Problems
Human - Planted too deep:
▪ smothering of roots (low O2)
▪ decay of bark
▪ most plants arrive on the
site too deep in the soilball
or container

10. Common Landscape Problems
Human - Planted too deep:
▪ smothering of roots (low O2)
▪ decay of bark
▪ most plants arrive on the
site too deep in the soilball
or container
➣ lift & replant if newly installed
➣ change grade (if on a slope)
➣ older plants decline & die
No trunk flare

11. Common Landscape Problems
Human - Small planting hole:
▪ roots do not get out of
planting hole
▪ pot-bound in container
▪ planting hole with glazed
sidewall
➣ lift and replant
➣ remove and replace

12. Common Landscape Problems
Human - Synthetics:
▪ confinement & girdling of roots
▪ no water movement
➣ remove & replant

13. Post-Weather Event Assessment
Synthetic twine & burlap

14. Common Landscape Problems
Circling roots (container):
▪ roots fail to grow into
backfill
➣ unwind roots at planting
Grown in container then
transplanted to field

15. Common Landscape Problems
The least winter hardy part of any plant is the root system.
Tree was planted in late fall
Rootball froze (13ºF) killing roots (fine roots did not regrow)
➣ remove and replace

16. Proper Installation
Planting Balled and Burlapped Trees and Shrubs in your
Landscape (HO-91) www2.ca.uky.edu/agcomm/pubs/ho/ho91/ho91.pdf
Planting Container- grown Trees and Shrubs in Your Landscape (HO-114)
www2.ca.uky.edu/agcomm/pubs/HO/HO114/HO114.pdf
Planting Bareroot Trees and Shrubs in Your Landscape (HO-113)
www2.ca.uky.edu/agcomm/pubs/HO/HO113/HO113.pdf

17. Common Landscape Problems
Selection (match plant to the site):
▪ soil type & pH
▪ drainage
▪ sun
▪ soil volume
▪ utilities (space above
ground)
Small tree (redbud) selected
for a large space

18. Site Assessment?

19. Common Landscape Problems
Site Assessment?
New subdivision
Minimal plantings

20. Common Landscape Problems
Selection (match plant to the site):
▪ compacted soil (poor turf)
▪ small planting hole
▪ rock (limestone? pH)
▪ redbud in full sun
▪ amended backfill

21. Common Landscape Problems
Human - Water:
▪ surface drainage?
▪ internal drainage?
▪ planting hole too deep?
▪ organic matter in
backfill (under ball)
▪ 1.5 inches per week
into root zone (most common cause of death in 1st
year after planting is water; too much or not enough)

22. Common Landscape Problems
Perk Test:
▪ dig a hole
▪ fill with water
▪ ≥1.0 inches per hour
Soil Percolation: A Key to
Survival of Landscape Plants. (ID-237) www2.ca.uky.edu/agcomm/pubs/ID/ID237/ID237.pdf

23. Common Landscape Problems
Human – compaction:
▪ flood plane species will
have surface roots. All
species will have surface
roots on compacted soils.
▪ poor infiltration
▪ poor percolation
▪ low soil oxygen
▪ poor root penetration

24. Common Landscape Problems
Human – compaction:
➣ prevention is easier &
cheaper than repair
➣ remove, amend & replace
damaged soil
Radial trenching with
air excavation tool
($22/linear foot)

25. Common Landscape Problems
Human – equipment:
▪ mowing equipment
➣ mulch to prevent
➣ protect from borers

26. Common Landscape Problems
Human – equipment:
▪ mowing equipment
▪ string trimmers
➣ mulch to prevent
➣ remove and replace

27. Common Landscape Problems
Human – chemical:
▪ what was applied?
(“true confession time”)
▪ sample to JD Green
▪ inform Dept. of Ag?
➣ Wait and see???
➣ Remove and replace
Hyvar® on
Acer rubrum

28. Common Landscape Problems
Human – mulch:
▪ maximum of 2 (maybe 3)
inches
▪ to dripline
▪ not against the trunk
(mice & voles)
▪ composted whole tree wood chips!

29. Common Landscape Problems
Human – mulch:
Avoid:
▪ volcano mulching
▪ “fat donuts”
▪ finely ground
(hydrophobic)
▪ gravel (does not add
organic matter)

30. Common Landscape Problems
Human – cutting roots:
▪ loss of stability
▪ stress
▪ stress related diseases
and insect pests
➣ while the cost of
tunneling is more than
the cost of trenching, it is less than the cost of
removing the tree. (long term vs. short term cost)

31. Common Landscape Problems
Human – pruning:
▪ topping
◦ aesthetics
◦ increases failures
◦ shortens life of tree
◦ wasted money

32. Common Landscape Problems
Animal:
▪ Deer

33. Common Landscape Problems
Animal:
▪ deer
▪ Male Dogs

34. Common Landscape Problems
Animal:
▪ deer
▪ Female Dogs

35. Common Landscape Problems
Animal:
▪ deer
▪ dogs
▪ Birds (sapsuckers)
◦ thin-bark trees
◦ early spring
◦ Migratory Bird Treaty Act
of 1918
◦ discourage them….
◦ Tanglefoot®

36. Common Landscape Problems
Animal:
▪ deer
▪ dogs
▪ Birds (woodpeckers)
◦ feeding on borers
◦ ash? (EAB)
Irregular spacing
Ragged edges

37. Resources: Dirr, Michael A. Manual of Woody Landscape Plants (5th ed.)
Dirr, Michael A. Dirr’s Encyclopedia of Trees and Shrubs
Fountain, et al. After Your Ash Has Died: Making an Informed Decision on What to Replant (ID-241)
Fountain, et al. What is Your Tree Worth? (ID-240)

38. Questions?