Leadership Team

Our Leadership Team is committed to making Yellowstone Landscape the country’s premier commercial landscape service company and to bringing that excellence to bear on behalf of our clients through industry-leading investments in safety, training, information systems, and execution.

Tim Portland (1)

Tim Portland

Chief Executive Officer

Tim Portland has led Yellowstone Landscape to record safety, customer satisfaction, growth, and overall business performance since joining the company in 2012. Yellowstone has expanded its operations by striving to deliver Excellence in Commercial Landscaping to demanding customers who value quality landscape service partnerships. Tim serves on the Board of Directors of the National Association of Landscape Professionals and chairs the association’s H-2B steering committee. He also serves on the Board of the Seasonal Employment Alliance, an advocacy organization focused on congressional reform of the guest worker visa programs that sustain seasonal businesses across the United States. Prior to joining Yellowstone, Tim was the CEO of United Subcontractors, a leading installer of building products. Over a ten-year period, he was the President of several divisions of Scotts Miracle-Gro, including the Ortho and Roundup brands, Scotts LawnService, and Scott’s International Professional business. He was previously an executive with Scientific-Atlanta (now part of Cisco), and a management consultant with McKinsey and Company. Tim holds an MBA from the University of Virginia’s Darden Business School and an undergraduate degree from Dartmouth College.

Tim Portland (1)

Tim Portland

Chief Executive Officer

Tim Portland has led Yellowstone Landscape to record safety, customer satisfaction, growth, and overall business performance since joining the company in 2012. Yellowstone has expanded its operations by striving to deliver Excellence in Commercial Landscaping to demanding customers who value quality landscape service partnerships. Tim serves on the Board of Directors of the National Association of Landscape Professionals and chairs the association’s H-2B steering committee. He also serves on the Board of the Seasonal Employment Alliance, an advocacy organization focused on congressional reform of the guest worker visa programs that sustain seasonal businesses across the United States. Prior to joining Yellowstone, Tim was the CEO of United Subcontractors, a leading installer of building products. Over a ten-year period, he was the President of several divisions of Scotts Miracle-Gro, including the Ortho and Roundup brands, Scotts LawnService, and Scott’s International Professional business. He was previously an executive with Scientific-Atlanta (now part of Cisco), and a management consultant with McKinsey and Company. Tim holds an MBA from the University of Virginia’s Darden Business School and an undergraduate degree from Dartmouth College.

Harry Lamberton

Harry Lamberton

President

Harry Lamberton joined Yellowstone in 2022 to drive continuous improvement in Yellowstone’s growth, quality, and safety applying expertise gained from over 20 years of leading environmental and sustainability businesses at Waste Management. Harry was most recently the Vice President of Waste Management’s Midwestern states, which he grew to over $1.4 billion in annual revenue, creating one of the largest regions in the company. His track record includes driving profitable growth in multiple operational assignments - including branch-based businesses, launching new and expanding existing business lines - including environmental remediation services, driving safety to record levels, and helping lead Waste Management’s focus on sustainability. Harry earned a BA from the University of New Hampshire and an MBA from the Goizueta School of Business at Emory University and serves on the Global Sustainability Centre’s Advisory Board for the Conference Board.

Harry Lamberton

Harry Lamberton

President

Harry Lamberton joined Yellowstone in 2022 to drive continuous improvement in Yellowstone’s growth, quality, and safety applying expertise gained from over 20 years of leading environmental and sustainability businesses at Waste Management. Harry was most recently the Vice President of Waste Management’s Midwestern states, which he grew to over $1.4 billion in annual revenue, creating one of the largest regions in the company. His track record includes driving profitable growth in multiple operational assignments - including branch-based businesses, launching new and expanding existing business lines - including environmental remediation services, driving safety to record levels, and helping lead Waste Management’s focus on sustainability. Harry earned a BA from the University of New Hampshire and an MBA from the Goizueta School of Business at Emory University and serves on the Global Sustainability Centre’s Advisory Board for the Conference Board.

Elise Johnson (1)

Elise Johnson

Senior Vice President, Human Resources

Elise Johnson has led Yellowstone Landscape’s Human Resources team needs since joining the company in 2010. Elise and her team are chiefly responsible for helping our local branch leaders find and recruit the talented and professional managers needed for continued strong growth and consistently excellent quality. She has also developed local support tools and implemented best practices for attracting and retaining frontline personnel, including benefits, rewards, and engagement programs designed to make Yellowstone the best place to work in the landscape industry. She navigates the company’s seasonal operating demands and decentralized business structure while ensuring regulatory compliance within a demanding, performance-driven culture. Elise earned a BA from Dickinson College and her MBA from Rutgers, The State University of New Jersey. Before joining Yellowstone, Elise held similar positions at prominent financial services firms in New York City.

Elise Johnson (1)

Elise Johnson

Senior Vice President, Human Resources

Elise Johnson has led Yellowstone Landscape’s Human Resources team needs since joining the company in 2010. Elise and her team are chiefly responsible for helping our local branch leaders find and recruit the talented and professional managers needed for continued strong growth and consistently excellent quality. She has also developed local support tools and implemented best practices for attracting and retaining frontline personnel, including benefits, rewards, and engagement programs designed to make Yellowstone the best place to work in the landscape industry. She navigates the company’s seasonal operating demands and decentralized business structure while ensuring regulatory compliance within a demanding, performance-driven culture. Elise earned a BA from Dickinson College and her MBA from Rutgers, The State University of New Jersey. Before joining Yellowstone, Elise held similar positions at prominent financial services firms in New York City.

Chris Adornetti (1)

Chris Adornetti

Vice President, Accounting

Since joining Yellowstone Landscape in 2015, Chris Adornetti has overseen all day-to-day Accounting and Finance operations of the company, including all treasury, insurance, tax, and legal requirements. Prior to joining Yellowstone, Chris spent 7 years at Harte Hanks, a publicly-traded marketing, data analytics, and logistics company, and previously worked in public accounting and internal audit. A two-time graduate of the University of North Florida, Chris holds a Bachelor’s degree in Accounting and a Master’s in Business Administration.

Chris Adornetti (1)

Chris Adornetti

Vice President, Accounting

Since joining Yellowstone Landscape in 2015, Chris Adornetti has overseen all day-to-day Accounting and Finance operations of the company, including all treasury, insurance, tax, and legal requirements. Prior to joining Yellowstone, Chris spent 7 years at Harte Hanks, a publicly-traded marketing, data analytics, and logistics company, and previously worked in public accounting and internal audit. A two-time graduate of the University of North Florida, Chris holds a Bachelor’s degree in Accounting and a Master’s in Business Administration.

Ben Collinsworth

Ben Collinsworth

Director, Operational Technology

Ben Collinsworth founded and managed his own successful commercial landscaping company for more than 20 years, Native Land Design operating locations in both Austin and Houston, Texas. In 2019, Ben partnered with Yellowstone and has since focused on expanding and implementing new technologies into the company’s operations. These include both software and systems tools and capabilities, and leading the testing and field practices for new advances in autonomous and robotic mowing opportunities and battery and electric powered devices. Ben is a proud graduate of Texas A&M University, where he played defensive end on the A&M football team.

Ben Collinsworth

Ben Collinsworth

Director, Operational Technology

Ben Collinsworth founded and managed his own successful commercial landscaping company for more than 20 years, Native Land Design operating locations in both Austin and Houston, Texas. In 2019, Ben partnered with Yellowstone and has since focused on expanding and implementing new technologies into the company’s operations. These include both software and systems tools and capabilities, and leading the testing and field practices for new advances in autonomous and robotic mowing opportunities and battery and electric powered devices. Ben is a proud graduate of Texas A&M University, where he played defensive end on the A&M football team.

James Herth (1)

James Herth

Senior Vice President, Business Development

Jim Herth became Yellowstone Landscape’s Vice President of Business Development in 2014, after joining the company in 2011 as a Branch Manager. “Coach” Jim is responsible for Yellowstone’s industry-leading sales team, a critical component of Yellowstone’s superior growth and track record with customers. A twenty-five-year industry veteran with a track record of managing multiple branches, delighting customers, and delivering profitable growth, Jim is a licensed Arborist and holds a Bachelor’s degree from Siena Heights University.

James Herth (1)

James Herth

Senior Vice President, Business Development

Jim Herth became Yellowstone Landscape’s Vice President of Business Development in 2014, after joining the company in 2011 as a Branch Manager. “Coach” Jim is responsible for Yellowstone’s industry-leading sales team, a critical component of Yellowstone’s superior growth and track record with customers. A twenty-five-year industry veteran with a track record of managing multiple branches, delighting customers, and delivering profitable growth, Jim is a licensed Arborist and holds a Bachelor’s degree from Siena Heights University.

Brian Martin (1)

Brian Martin

Vice President, Standards, Safety, and Training

With nearly thirty years of experience in the commercial landscaping industry, Brian Martin has performed several leadership roles for Yellowstone, including prior line management of all of Yellowstone’s Florida operations. To help meet the demands of Yellowstone’s rapid growth, Brian took on leadership of Yellowstone’s Standards, Safety, and Training needs. He is responsible for developing and applying the best practices of the company across varied regions and branch locations while continuing to increase operational efficiency and quality. Through his dedicated Health and Safety team, the company has achieved some of the lowest incident rates in the landscape industry and is routinely recognized for the proactive approach that Yellowstone takes toward safety and protecting its employees, clients, and their properties. Brian personally leads employee training and development for Branch Managers, Account Managers, Irrigators, and other Horticultural Personnel. Brian is a graduate of Virginia Tech’s Landscape Architecture program and holds an MBA from the University of Florida.

Brian Martin (1)

Brian Martin

Vice President, Standards, Safety, and Training

With nearly thirty years of experience in the commercial landscaping industry, Brian Martin has performed several leadership roles for Yellowstone, including prior line management of all of Yellowstone’s Florida operations. To help meet the demands of Yellowstone’s rapid growth, Brian took on leadership of Yellowstone’s Standards, Safety, and Training needs. He is responsible for developing and applying the best practices of the company across varied regions and branch locations while continuing to increase operational efficiency and quality. Through his dedicated Health and Safety team, the company has achieved some of the lowest incident rates in the landscape industry and is routinely recognized for the proactive approach that Yellowstone takes toward safety and protecting its employees, clients, and their properties. Brian personally leads employee training and development for Branch Managers, Account Managers, Irrigators, and other Horticultural Personnel. Brian is a graduate of Virginia Tech’s Landscape Architecture program and holds an MBA from the University of Florida.

Gabe Perez (1)

Gabe Perez

Director, IT & Business Systems

Since joining Yellowstone Landscape in 2018, Gabe Perez has been responsible for the company’s critical technology infrastructure and systems. With a background in programming, quality assurance, and business intelligence, Gabe and his team deliver the most efficient and user-friendly information systems and reporting possible. Leaders at all levels of the company rely on the work of Gabe’s team when making decisions about how to best manage their parts of the business and drive the overall performance of the company. A native of Flagler County, Florida, Gabe completed his Associate’s degree at the University of South Florida before earning his Bachelor of Science in Information Technology and Management at Keiser University in Jacksonville.

Gabe Perez (1)

Gabe Perez

Director, IT & Business Systems

Since joining Yellowstone Landscape in 2018, Gabe Perez has been responsible for the company’s critical technology infrastructure and systems. With a background in programming, quality assurance, and business intelligence, Gabe and his team deliver the most efficient and user-friendly information systems and reporting possible. Leaders at all levels of the company rely on the work of Gabe’s team when making decisions about how to best manage their parts of the business and drive the overall performance of the company. A native of Flagler County, Florida, Gabe completed his Associate’s degree at the University of South Florida before earning his Bachelor of Science in Information Technology and Management at Keiser University in Jacksonville.

Timothy Sherman

Timothy Sherman

Vice President, Finance

Timo Sherman leads all Financial Planning and Analysis activities for Yellowstone Landscape. Timo joined Yellowstone in 2008, serving customers and leading service teams as an Account Manager and Branch Manager before moving into Finance. Timo and his team support our regional and branch leadership by providing important financial information to assist in their decision-making processes. He is responsible for all analyses and recommendations on key issues with material impact on the company and drives our budgeting, planning, and forecasting processes. Timo further leads the analysis and execution of all acquisition evaluations and market expansions by Yellowstone. Timo holds a Bachelor’s degree in Accounting from the University of Florida and an MBA from Jacksonville University.

Timothy Sherman

Timothy Sherman

Vice President, Finance

Timo Sherman leads all Financial Planning and Analysis activities for Yellowstone Landscape. Timo joined Yellowstone in 2008, serving customers and leading service teams as an Account Manager and Branch Manager before moving into Finance. Timo and his team support our regional and branch leadership by providing important financial information to assist in their decision-making processes. He is responsible for all analyses and recommendations on key issues with material impact on the company and drives our budgeting, planning, and forecasting processes. Timo further leads the analysis and execution of all acquisition evaluations and market expansions by Yellowstone. Timo holds a Bachelor’s degree in Accounting from the University of Florida and an MBA from Jacksonville University.

Jim Sivils

Jim Sivils

Regional Vice President

Jim Sivils joined Yellowstone Landscape in 2010 after 20 years of owning and operating Texas Services – one of Houston’s most successful tree and landscape services companies. Jim has overseen Yellowstone’s extraordinary growth in Texas and is responsible for all Yellowstone Landscape operations across the state.

Jim Sivils

Jim Sivils

Regional Vice President

Jim Sivils joined Yellowstone Landscape in 2010 after 20 years of owning and operating Texas Services – one of Houston’s most successful tree and landscape services companies. Jim has overseen Yellowstone’s extraordinary growth in Texas and is responsible for all Yellowstone Landscape operations across the state.

Brian Wester (1)

Brian Wester

Senior Vice President, Operations

Brian Wester is Yellowstone Landscape’s Senior Vice President of Operations, responsible for the company’s operations across the Southeast United States. Brian joined the company in 2003 as an Account Manager in Palm Coast, Florida. He launched and managed multiple branch locations across Central Florida before being promoted to Regional Vice President in 2011. He led the post-recession turnaround of the company’s Georgia and South Carolina operations and has since returned to Florida, now leading operations across three states for Yellowstone. Brian holds an Associate of Science degree in Golf Course Operations, a Bachelor of Science degree in Business and Finance, and earned his MBA from the University of Florida.

Brian Wester (1)

Brian Wester

Senior Vice President, Operations

Brian Wester is Yellowstone Landscape’s Senior Vice President of Operations, responsible for the company’s operations across the Southeast United States. Brian joined the company in 2003 as an Account Manager in Palm Coast, Florida. He launched and managed multiple branch locations across Central Florida before being promoted to Regional Vice President in 2011. He led the post-recession turnaround of the company’s Georgia and South Carolina operations and has since returned to Florida, now leading operations across three states for Yellowstone. Brian holds an Associate of Science degree in Golf Course Operations, a Bachelor of Science degree in Business and Finance, and earned his MBA from the University of Florida.

Blake Singleton

Blake Singleton

Regional Vice President

Blake Singleton joined Yellowstone Landscape in 2016 as Director of North Carolina Maintenance Operations when Yellowstone expanded to the state. Blake previously held account, branch, sales, and regional management positions for other highly respected landscape firms. Since becoming Yellowstone’s Mid-Atlantic Regional Vice President, Blake has further led Yellowstone’s growth across the region, and now manages branch locations spanning 6 states. Blake holds a Bachelor of Science in Business and Economics from the University of South Carolina Upstate.

Blake Singleton

Blake Singleton

Regional Vice President

Blake Singleton joined Yellowstone Landscape in 2016 as Director of North Carolina Maintenance Operations when Yellowstone expanded to the state. Blake previously held account, branch, sales, and regional management positions for other highly respected landscape firms. Since becoming Yellowstone’s Mid-Atlantic Regional Vice President, Blake has further led Yellowstone’s growth across the region, and now manages branch locations spanning 6 states. Blake holds a Bachelor of Science in Business and Economics from the University of South Carolina Upstate.

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