arboricultural society of michigan 2012
TRANSCRIPT
Review of the Plant Growth
Regulator (PGR) Program
Michigan State University
Landscape Services Department
PGR (Paclobutrazol)
Paclobutrazol inhibits the production of
gibberellin in plants
New growth is reduced
Growth is controlled for 2-3 years
Safety and ecology
Sub-soil applied
Low water solubility product
Breaks down in the soil quickly
Low toxicity LD50: >5,000 mg/Kg
Plant Health Benefits
Increased fine root-hair production
Increased woody-root production with repeated
applications
Increased carbohydrate storage
Increased resistance to drought and disease
Notably improved foliage color and appearance
Uses for PGR’s
Preservation of plant material impacted by
construction activities
Promote quicker establishment of new trees
Preservation of declining or over-mature trees
Reduction in watering volume and frequency
Reduction in pruning intensity and frequency
How do PGR’s Reduce Pruning?
Normal Growth
Controlled Growth Using a PGR
Yr 0
Yr 6 Yr 2 Yr 1 Yr 0
Yr 1
Yr 5 Yr 4 Yr 3
PGR App PGR App
2012 2013
1. Wilson Hall
Before After
Untreated PGR
1. Wilson Hall
Untreated
PGR
1. Wilson Hall
2. Birch Road
Untreated (East Side) PGR (West Side)
2. Birch Road
Untreated PGR
3. Shaw Hall
Untreated PGR
3. Shaw Hall
Untreated PGR
4. Shaw Lane
Untreated (South Side) PGR (North Side)
4. Shaw Lane
Untreated PGR
5. Owen Graduate Center
Untreated PGR
PGR
6. Hubbard Hall
Untreated (South Side) PGR (North Side)
Results
Thus far in 2012, we have realized significant
growth control on most shrubs treated
spring/early summer
Severe drought stress was reduced by 50% by
utilizing PGR on trees (<10” DBH)
Plant health and appearance improved with
PGR
$0.00
$20.00
$40.00
$60.00
$80.00
$100.00
$120.00
Taxus sp. Forsythia sp. Euonymus sp. Viburnum sp.
(Cost to Use PGR Versus One Pruning Cycle Including Labor and Equipment)
Cost Comparison per 100 Sq. Ft.
PGR Cost
Pruning Cost
Accomplishments to Date
789 trees treated
1,731 individual shrubs treated
64,613 square feet of shrub beds treated
All work was completed in 152 hours with two
applicators
78 gallons of concentrated Paclobutrazol applied
Conclusion
PGR is an innovative and cost effective tool to
preserve MSU’s environmental resources
PGR will increase the longevity and aesthetic
quality of plant materials on campus
Re-allocating labor will allow Landscape
Services to maintain a high quality of service to
the MSU campus