Professional Certification
How to Verify a Landscaper or Arborist Certification
Landscapers and arborists are largely unregulated at the state level in most of the U.S. — anyone can call themselves a landscaper or tree service. The meaningful credentials are voluntary certifications from professional associations like ISA and NALP, plus state pesticide applicator licenses where chemicals are applied. Here is what to verify and where.
Quick answer
For arborists: verify ISA Certified Arborist status at treesaregood.org/verify. For landscapers: verify NALP certifications at landcarenetwork.org. If pesticides will be applied (fertilizers, herbicides, insecticides), separately verify a state pesticide applicator license through your state department of agriculture. There is no single national landscaper license.
ISA Certified Arborist
The International Society of Arboriculture (ISA) Certified Arborist credential is the most widely recognized and verified arborist certification in North America. It requires a combination of documented arboricultural experience, a written exam, and ongoing continuing education to maintain.
ISA also issues additional specialty credentials for Certified Arborists who demonstrate advanced expertise:
- ISA Certified Arborist: Core credential; general tree care knowledge and practice
- ISA Board Certified Master Arborist (BCMA): Senior credential; most rigorous ISA certification; requires extensive experience, references, and a more comprehensive exam
- ISA Certified Tree Worker (CTW): Credential for climbing and field workers rather than supervisors and consultants
- ISA Utility Specialist: Specialty for utility line clearance arborists
- ISA Municipal Specialist: Specialty for urban forestry and municipal tree programs
How to verify ISA Certified Arborist status
- Go to treesaregood.org (ISA's public site)
- Click "Find an Arborist" or "Verify a Credential"
- Search by name, zip code, or certification number
- Active certifications show current status and expiration date
ISA certification is maintained through a 3-year renewal cycle requiring Continuing Education Units (CEUs). An arborist who does not renew loses "Certified Arborist" status even if they were previously certified. Always verify current status, not just whether someone was ever certified.
NALP landscape professional certifications
The National Association of Landscape Professionals (NALP) offers a certification program for landscape industry workers. NALP certifications cover landscape technicians, supervisors, and managers through a combination of knowledge testing and field skills assessment.
| NALP Credential | Focus |
|---|---|
| Landscape Industry Certified (LIC) — Technician | Lawn care, ornamental maintenance, irrigation, and exterior maintenance tasks |
| LIC — Supervisor | Team management, production planning, and client communication |
| Landscape Management Network (LMN) Certification | Business management within the landscape industry |
Verify NALP credentials at landcarenetwork.org. NALP certifications are much less common than ISA credentials — their absence does not indicate incompetence, but their presence is a meaningful differentiator.
State pesticide applicator license
Any landscape contractor who applies fertilizers, herbicides, insecticides, or fungicides for hire must hold a state pesticide applicator license — even if those chemicals are sold over the counter. This is a legal requirement in all 50 states, not a voluntary credential.
The relevant license categories typically include:
- Ornamental and Turf: Application of pesticides to landscape plants, trees, shrubs, and lawns
- Right-of-Way: Application along roadsides, utility corridors, and similar areas
- General Pest: Structural pest treatments (less common for landscape-only contractors)
Verify the pesticide applicator license through your state's department of agriculture (see the pest control license article for a list of state portals). A landscaper applying chemicals without this license is operating illegally.
Tree work: why credential verification matters
Tree removal and pruning near structures and power lines is hazardous work. Unlicensed or uncertified tree services can cause significant property damage, injury, and liability exposure. Red flags for unqualified tree services include:
- Offering to do work for cash only with no written contract
- Arriving unsolicited after a storm offering immediate discounted removal
- Unable to provide proof of insurance on request
- No ISA certification or equivalent arborist credential
- Recommending "topping" trees (an internationally condemned and harmful practice)
Insurance verification
Landscape and tree work involves equipment, heights, and proximity to structures. Always verify:
- General liability insurance: Minimum $1M per occurrence. Request a COI. Particularly important for tree work near structures.
- Workers' compensation: Required for employees in most states. If a worker is injured on your property without coverage, liability may fall to you as the property owner.
Verification checklist
- 1. For arborists: verify ISA Certified Arborist or BCMA status at treesaregood.org — confirm Active and not expired
- 2. For landscapers: optionally verify NALP Landscape Industry Certified status at landcarenetwork.org
- 3. If pesticides will be applied: verify state pesticide applicator license (Ornamental and Turf category) through the state department of agriculture
- 4. Request a Certificate of Insurance (COI) and verify general liability coverage
- 5. Verify workers' compensation coverage, especially for tree work with climbers
- 6. For any tree work near structures or power lines, require a written contract with scope, liability, and cleanup terms
Verify horticulture and landscape program accreditation
Arborists and landscape managers who completed horticultural or urban forestry programs should have trained at accredited institutions. Use VerifyED to confirm school accreditation before accepting educational credentials.
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