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Certified Professional Horticulturist
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Administered by the ASHS Certified Professional Horticultural Board, (CPHB), a CPH certification is granted based on scholarly presentation, required participation in continuing education programs in particular areas of specialization, and work experience supported by references. Individuals certified by the CPHB have met educational and practical experience standards, subscribe to the CPH Code of Ethics, and qualify for identification and recognition as professionals of excellence in their field.

United States


Keith M. Backman, CPH
1511 Middleton St., Hanford, CA 93230
Phone: 559.584.8322
Areas of Expertise: Groundwater Quality; Soil Plant Analysis; Crop Quality; Saline Soils

Thomas Confal, CPH
14675 Moon Shadow Rd., Nevada City, CA 95959
Areas of Expertise: Pest Management; Irrigation; General Horticulture; Turf Management


Dawn A. De Vos, PhD, CPH
De Vos & Associates
1961 Main Street, PMB 148, Watsonville, CA 95076-3027
Phone: 831.685.1875
Area of Expertise: Crop Science, Crop Production, Crop Marketing, Crop Breeding


Neal E. De Vos, PhD, CPH
De Vos & Associates
1961 Main St., PMB 148, Watsonville, CA 95076-3027
Phone: 831.688.9577
Areas of Expertise: General Horticulture; Olericulture; Plant Breeding; Seed Production

Deborah Ellis,  CPH
Company: Deborah Ellis, MS.  Consulting Arborist & Horticulturist
PO Box 3714, Saratoga, CA 95070

Areas of Expertise: Diagnostics, Forensic, Research & General Analysis, Consultation & Documentation in Horticulture, Arboriculture & Agriculture

Since 1984, horticultural and arboricultural diagnostics, research, insurance investigation, expert witness work and professional consultation and documentation in all phases of horticulture and arboriculture.  I provide a broad range of technical and advisory services for professionals in the California Landscape industry: architects, contractors, golf courses, growers, nursery industry, maintenance, planners, and municipalities. Also: attorneys, insurance companies, utilities, private individuals and others requiring horticultural expertise.


R. Stanley Grant, CPH
1015 Yosemite St., Turlock, CA 95380
Phone: 209.664.7656
Areas of Expertise: Viticulture; Soil Management; Crop Production; Farm Management 

Larry D. Knerr, CPH
Tanimura & Antle
Salinas, CA 93901
Phone: 831.455.4018
Areas of Expertise: General Horticulture; Plant Breeding; Plant Genetics; Weed Science

Michael D. McCullough, CPH
19310 Acclaim Drive
Salinas, CA 93908
Areas of Expertise: General and Ornamental Horticulture; Plant Pathology; Turfgrass Management 

Robert L. Mazalewski, CPH
PO Box 72809, Davis, CA 95617-2809
Phone: 530.902.8330
Areas of Expertise: General Horticulture; Ornamental Horticulture; Nursery Management 

Robert L. Mikkelsen, CPH
International Plant Nutrition Institute
4125 Sattui Court, Merced, CA 95348
Phone: 209.725.0382
Areas of Expertise: Soil Fertility, Plant Nutrition, Soil Chemistry, Fertilizer Use

Rob Mikkelsen is the Director of Western North America programs for the International Plant Nutrition Institute in 2007. He was previously Professor of Soil Science at North Carolina State University (NCSU) in Raleigh and Soil Chemist at the National Fertilizer Development Center at Muscle Shoals, Alabama. He is widely known for his research and expertise in nutrient management and writes widely on topics related to plant nutrition, nutrient management, environmental issues, and fertilizer technology.  In addition to being a Certified Professional Horticulturist, Rob is a Certified Crop Advisor. A native of California, Dr. Mikkelsen earned his B.S. degree in Agronomy/Soils at Brigham Young University and a PhD in Soil Science at University of California, Riverside. Rob regularly writes in his nutrient management blog.


Craig Interian, CPH
932 Alphonse Street
Santa Barbara, CA 93103
Phone: 805-886-2424
Areas of Expertise: Estate Garden Management, Horticulture Consultant, Certified Master Arborist, Plant Procurement, Construction Mitigation, Tree Protection Standards

I have a BS in Environmental Horticulture from Cal Poly San Luis Obispo. In my years of experience I have managed and cared for almost every type of specialized garden imaginable while working as a head groundskeepers on many large estates in Montecito, Ca. I have a strong background in crew management and staff training. I became a Certified Arborist in 2004 and then a Master Arborist in 2014. I have extensive experience in overseeing large scale tree and plant installation and implementing tree protection guidelines for construction, as well as post-care mitigation of planting problems. I left my job as an Estate groundskeeper in October 2014 and I am currently working as a consultant in both horticulture and arboriculture, and in plant procurement for homeowners and designers. I worked many years as a USFS Hotshot on the Plumas National Forest in California while earning my Bachelors degree.


Kerrie B. Badertscher, CPH
Otoké Horticulture LLC, Specialty Crop Consulting
PO Box 517, Allenspark, CO 80510
Areas of Expertise: Cannabis Consultant


Paul D. Orpello, CPH
321 Springhill Ave, Wilmington,DE 19809
Areas of Expertise: General Horticulture; Nursery Management; Pest Management; Soil Management


Mary L. Lamberts, CPH
Dade Co. Coop. Ext.
18710 SW 288th St., Homestead FL 33030-2309
Phone: 305.248.3311, ext. 234
Areas of Expertise: International Horticulture; Olericulture; Tropical Crops 


Alicia J. Whidden, CPH
5110 Ralston Rd., Lakeland, FL 33811
Phone: 813.744.5519, ext. 134
Areas of Expertise: Plant Pathology; Small Fruit Culture 

Uday K. Yadav, CPH
HCS Inc.
764 Silverwood Drive, Lake Mary, FL 32746
Areas of Expertise: General Agronomy; Crop Production; General Horticulture; Turfgrass Management


John K. Mockus, CPH

714 S. River Rd., Naperville, IL 60540
Phone: 630.393.4554
Areas of Expertise: General and Ornamental Horticulture; Pest Management; Pesticide Use


Christopher Forth, CPH, CPAg, CCA, VA Nutrient Planner
Bel Air, MD 21015
Phone: 443.868.3223 • Fax: 901.597.0071
Areas of Expertise: Turfgrass Management; Ornamental Horticulture; Fertilizer Use; Pest Management

Chris Forth began his career with ChemLawn, now TruGreen as Lawn Specialist, managing a 35 acre turf and landscape plant research farm and working as Region Technical Manager for 32 years supporting branch operations in DE, MD, NJ, NC, PA and VA. His work has included design and implementation of lawn and landscape maintenance programs for commercial and residential properties, development of and conducting technical training, regulatory compliance and public relations. In 2013, Chris was appointed Technical Training Manager with responsibility for development and delivery of technical training for the newest associates with focus on landscape plant maintenance and care.


Steven A. Van Natta, CPH
350 Hilltop Ave., Owatonna, MN 22060
Phone: 507.451.4144 • Fax: 507.451.7004
Areas of Expertise: Fertilizer Technology; Irrigation & Drainage; Soil Management; Turfgrass Management 

David C. Zlesak, CPH
1500 Fairmount Ave., St. Paul, MN 55105
Phone: 763.486.7920
Areas of Expertise: Ornamental Horticulture; Plant Breeding; Plant Propagation, Tissue Culture


Gary R. Bachman, PhD
Coastal Research & Extension Center
Mississippi State University
1815 Popps Ferry Road, Biloxi, MS 39532
Phone: 228.546.1009
Areas of Expertise: Nursery Management, Horticulture (general), Ornamental Horticulture, Greenhouse Production

Lise Pittman Foy, CPH
MS Agriculture & Forestry Museum
Mississippi Department of Agriculture & Commerce
1150 Lakeland Drive, Jackson, MS 39216
Phone: (601)-432-4512
web: Mississippi Ag & Forest Museum
Areas of Expertise: General Horticulture, Agritourism, Landscape Design

Since 2004, it has been my goal to inspire people to appreciate and enjoy the tremendous beauty of the diverse plant world.  It is my goal to promote sustainable horticultural practices through community events, projects and landscapes and to communicate the value of past and present Mississippi agricultural lifestyles, relationships and practices. It is also my ambition to be a life-long student of all the many facets of horticulture.

Richelle A. Stafne, CPH

13 Woodridge Ln
Picayune, MS 39466
Phone: 601-798-9434  

Areas of Expertise: General and Ornamental Horticulture


Lala A. Kumar, CPH
404 NE Victoria, Lee Summit, MO 64086
Phone: 815.252.5051
Areas of Expertise: General and International Horticulture; Olericulture; Pomology

North Carolina

John D. Abbott, CPH
Syngenta Crop Protection
PO Box 18300, Greensburo, NC 27419
Phone: 336.632.7074
Areas of Expertise: Pest Management; Pesticide Use; Product R&D; Weed Science 

Michael C. Barnes, CPH
Duke Biology
130 Science Drive, Rm. 137, Bio. Sci. Bldg.
Duke Box 90338, Durham NC 27705
Phone: 919.328.9475 • Fax: 919.660.7265
Areas of expertise: Ornamental Horticulture, Floriculture, Greenhouse Production 

Christopher L. Gunter, CPH 
North Carolina State University
230 Kilgore Hall Box 7609, Raleigh, NC 27695-7609
Phone: 919.513.2807 •F ax: 919.515.2905
Areas of Expertise: Crop Physiology; Crop Production; Crop Quality; Plant Nutrition 

Michael T. Morrison, CPH
USDA Risk Mgmt.
4405 Bland Road #165, Raleigh, NC 27609
Phone: 919.875.4950
Areas of Expertise: General and Ornamental Horticulture; Nursery Management; Plant Propagation 

Charles B. Williams III, CPH
1101 Upper Reach Dr., Wilmington, NC 28409
Phone: 910.313.6785
Areas of Expertise: Ornamental and International Horticulture; Pesticide Use; Turfgrass Management


Janet C. Cole, CPH
Oklahoma State University
Dept. of Hort., 360 Ag Hall, Stillwater, OK, 74078-6027
Phone: 405.744.5770
Areas of Expertise: Ornamental Horticulture; Nursery Management 

James E. Motes, CPH
2819 E. Richmond Rd., Stillwater, OK, 74075-1766
Phone: 405.372.4634
Areas of Expertise: Best Management Practices; Crop Production; General Horticulture; Olericulture 

Albert J. Sutherland, CPH, CCA
OSU Mesonet Agricultural Coordinator, OSH Biosystems and Agricultural Engineering National Weather Center
120 David L. Boren Blvd., Suite 2900, Norman, OK 73072-7305
Phone: 405.325.3463 • Cell: 405.974.1977
Areas of Expertise: Agricultural Climatology; Computer Uses; General Horticulture 

Steve Upson
924 Souix Street, Ardmore, OK 73401
Phone: 580.224.6433 • Fax 580.224.6420
web: The Samuel Roberts Noble Foundation
Areas of Expertise: Irrigation; Olericulture; Small Fruit Culture; Soil Fertility


Don Richards, President, CPH
Applied Horticultural Consulting, Inc.
PO Box 2355, Lake Oswego, OR, 97035-1420
Phone: 503.756.5198
Fax: 503.699.9366
Areas of Expertise: Crop Marketing; Horticulture; Ornamental Nursery Management 

Clinton C. Shock, CPH
Oregon State Univ., Malher Expt. Station
595 Onion Ave., Ontario, OR, 97914
Phone: 541.889.2174
Areas of Expertise: 
Best Management Practices; Crop Ecology; Crop Production; Irrigation and Drainage


John S. De Noma CPH
980 New Road, Orrtanna, PA, 17353
Phone: 717.338.9990
Areas of Expertise: Ornamental Horticulture; Pesticide Use; Soil Fertility; Turfgrass Management 

Michael D. Orzolek, CPH
The Pennsylvania State University
203 Tyson Bldg., University Park, PA, 16802
Phone: 814.863.2251
Areas of Expertise: Crop Production; General Horticulture; Olericulture

South Carolina

Michael T. Martin, Jr.
432 Boys Acres Drive, Seneca, SC 29678
Phone: 864.710.8934
Areas of Expertise: Plant Physiology, Plant Propagation, Nursery Management, Ornamental Horticulture


Robert Richardson, CPH
210 St. James West
Cookville, TN 38501

David Vandergriff, CPH
University Extension - Knox County
City County Bldg., 400 W. Main St., Suite 560, Knoxville, TN 37902-2411
Phone: 865.215.2340


Gregory T. Church CPH
Texas A&M University
1408 Lombardy Way, Allen, TX 75002
Phone: 972.548.4232; 972-359-1416 (home)
Areas of Expertise: Plant Pathology; General and Ornamental Horticulture; Pest Management 

Leslie Finical Halleck, CPH
Halleck Horticultural
9540 Garland Rd. Ste. 381-342
Dallas, TX 75218
Phone: 214.733.3407
Areas of Expertise: General Horticulture, Garden Center Management, Ornamental Horticulture, Plant Ecology

Leslie is a dedicated horticulturist with 20 years of green industry experience.  She specializes in vegetable gardening, edible landscaping, organics, ornamentals and urban backyard livestock. She earned her MS in Horticulture at Michigan State University and her BS in Biology/Botany from the University of North Texas. Her previous positions include Director of Horticulture Research at the Dallas Arboretum, where she was responsible for creating and developing their well-known plant trials program, as well as establishing an All-America Selections Garden. For the past eight years she served as General Manager for North Haven Gardens, a well-respected independent garden center in Dallas. She currently runs her own company, Halleck Horticultural, through which she provides horticultural marketing, business consulting, social media management, and content generation to green industry businesses; as well as horticultural consulting for commercial and residential projects.


Leon R. Macha, CPH
1304 Meadow Creek Dr., El Campo, TX, 77437
Phone: 979.543.2445 • Cell: 979.320.4434
Areas of Expertise: General and Ornamental Horticulture; Nursery Management


Terry G.L. Ferriss, CPH
University of Wisconsin-River Falls
307 Ag. Science, River Falls, WI, 54022
Phone: 715.425.3535
Areas of Expertise: Floriculture; General Horticulture; Greenhouse Production


Karen L. Panter, CPH
Univ. of Wyoming, College of Agr., Dept. 3354
1000 E. Univ. Ave., Laramie, WY, 82071
Phone: 307.766.5117


Casey P. Seals, CPH
1766 N 18th Street
Laramie, WY 82072
Areas of expertise: Garden Center Management, Greenhouse Production, Horticulture, General, Irrigation

Outside the United States


Jeffrey P. Norrie, CPH
30 Brown Ave., Dartmouth, NS, B3B 1X8, Canada
Phone: 902.468.2840
Areas of Expertise: General Agronomy; Plant Physiology; Crop Science; Greenhouse Production

Jeff grew up on a beef farm in rural Nova Scotia, Canada. His BSc (Mount Allison, 1985) focused on animal physiology and marine sciences with minors in plant physiology and biophysics. His MSc (Dalhousie, 1988) examined environmental and plant hormone interactions in Integrated Cereal Management research. His PhD (Laval, 1992) involved research on greenhouse crop nutrition and automated fertigation systems while his post-doctoral research looked at soil amendments and fertility management in Turf and Ornamentals. Jeff has served as the Agricultural Research Manager for Acadian Seaplants Limited (ASL) since 1995. Based in Dartmouth, NS, ASL is an innovative company specializing in marine plant products for the Asian food market, the botanical industry, feed/food ingredients and the fertilizer/biostimulant industry. Jeff currently oversees programs in international fundamental and applied research, and provides technical support on the use of marine plant products and extracts the world over. With the help of French and Spanish he picked up along the way, Jeff’s networking, seminars and projects take him into over 40 countries. He is active in several professional societies having served as president of the Nova Scotia Institute of Agrologists, the Plant Growth Regulation Society of America, and he’s currently a VP with the American Society for Horticultural Science. All told, Jeff’s passion remains in connecting grower concerns with researcher solutions, and helping to build sustainable crop programs in both advanced and developing countries. 

Muhammad Saeed
Proplant Propagation Services, Ltd.
2401 Hwy #6, Jarvis ON N0A 1J0
Phone: 519.587.2235 • Fax: 519.587.2236 • Cell: 519.410.5665
Areas of Expertise: Greenhouse Production; Plant Propagation; Plant Physiology; Nursery Management


Jim Hole, CPH
101 Riel Drive
St. Albert, AB T8N 3X4
Phone: 780-419-6802
Fax: 780-459-6042

Northern Mariana Islands (U.S. Territory)

Dilip Nandwani, CPH
Northern Marianas College
PO Box 501250, Saipan, MP 96950, Northern Mariana Islands
Areas of Expertise: Tissue Culture (Micro and Macro Propagation); Molecular Biology; Plant Pathology

1018 Duke Street
Alexandria, VA 22314
Phone: 703.836.4606