What are the biggest red flags when hiring a landscaper?

Landscaper red flags cluster around four unlicensed-work patterns plus the standard contractor red flags. The downsides are dead sod within 30 days, retaining walls that fail and damage your house, irrigation cross-contamination of municipal water, EPA exposure for unlicensed pesticide application, and design work that fails permit.

Irrigation work without an irrigation contractor license. Tying into the municipal water supply requires backflow prevention, and most states require a separate irrigation contractor license to install. Texas (TCEQ Licensed Irrigator), Florida (DBPR Irrigation Contractor), California (under C-27 landscaping). An unlicensed irrigation install can contaminate the municipal water supply (cross-connection), triggering water department fines and homeowner liability. Verify the irrigation credential separately from the landscape contractor credential.

Pesticide or herbicide application without an applicator license. Commercial application of pesticides — even general-use products like Roundup applied commercially — requires a state Department of Agriculture applicator license in every state. Texas Commercial Applicator (TDA), California Qualified Applicator License (DPR), Florida Limited Lawn and Ornamental (DACS). A landscaper spraying weed-and-feed commercially without this license is operating illegally, and the homeowner can be cited for hiring an unlicensed applicator.

Retaining walls over 4 feet without engineered design. Most state and municipal codes require engineered design (stamped by a licensed engineer or landscape architect) for retaining walls over 4 feet (sometimes 3 feet). An undersized retaining wall — built without proper drainage, footing depth, or geogrid reinforcement — fails in the first heavy rain and can damage your foundation. The landscaper who quotes a 5-foot retaining wall as a stack-stone weekend project without engineering is the red flag.

Sod with no soil prep or warranty. The landscaper rolls out sod over compacted clay or weed-killed grass with no rototilling, soil amendment, or topsoil. The sod dies in 30 days. The "free re-do" promised verbally never materializes. Defense: require written sod warranty (typically 30-60 days for replacement if the sod dies due to installation), and require visible soil prep (rototilling, compost, topsoil) before sod arrives.

Design work over the state landscape architect threshold without a landscape architect. 49 states (all except Illinois historically) license landscape architects, with state-specific dollar or scope thresholds for when a licensed landscape architect is required vs. when a landscape designer can work. Pool decks, complex hardscape, and grading typically require a landscape architect.

Large upfront deposit. California caps at 10% or $1,000 for licensed contractors. Anything above 20% upfront in cash from a landscaper, especially after a major storm, is preparing-to-disappear behavior.

No written planting plan. "We'll plant some shrubs" is not a plan. A real landscape installation specifies plant species (botanical name), size at installation (1-gallon, 5-gallon, 15-gallon), quantity, location, soil amendment, mulch type and depth, and irrigation zone assignment.

Lowest bid by 30%+. The cheap quote typically substitutes 1-gallon plants for 5-gallon, skips soil prep, undersizes the drainage, or omits the irrigation entirely. The plants die or the drainage fails by year two.

Missing license in license-required states. California C-27, Arizona C-21, Florida Certified Landscape Contractor, Oregon CCB. Plus separately verifying the irrigation and applicator credentials.

Groundcheck (earthmove.io/trust) verifies the state landscape contractor license, surfaces court records, OSHA citations, and BBB complaints. It does not verify the irrigation or applicator credentials in every jurisdiction yet — check those at the state Department of Agriculture and TCEQ/equivalent water board separately. For state-specific thresholds, see earthmove.io/trust/license/landscaper/[state].