How Longmont Handles Landscaping Rules: A Practical Guide

Longmont maintains 106 local ordinances across all categories, and 8 of those deal specifically with landscaping rules. Here is a breakdown of what the city actually requires, what is prohibited, and where Longmont falls on the strict-to-permissive spectrum compared to other cities.

Grass Height Limits

Longmont Code Enforcement enforces a 12-inch maximum height for weeds and grass on private property. The rule is administered by the Code Enforcement Office (303-651-8695) under the City's nuisance and weed-control authority and applies to all land within city limits, including city-owned land.

Key details: Max Height: 12 inches (weeds and grasses). Enforcing Agency: Longmont Code Enforcement. Owner Duty: LMC 13.24.020 — to center of alley. State Overlay: Colorado Noxious Weed Act. Report Violations: 303-651-8695 / ServiceWorks.

Code Enforcement issues a written notice to abate (typically 7-10 days). Failure to mow can result in the City contracting mowing services and assessing the cost plus an administrative fee as a lien against the property. Continued violations are charged as municipal nuisance violations subject to Municipal Court fines.

Tree Removal & Heritage Trees

Removal of a healthy, high-value tree on City property or in the public ROW requires a Forestry Services permit and triggers appraisal and mitigation under LMC 13.24.110. The City Forester sets the appraised value, and equivalent replacement value must be paid or planted. Stump grinding is required with every approved removal.

Key details: Code Section: LMC 13.24.110 (Tree Protection). Permit Issuer: Longmont Forestry Services. Appraisal Method: ISA trunk-formula by City Forester. Stump Grinding: Required with all removals. Who Must Perform: City-licensed Tree Contractor (LMC 6.88).

Removing a city or ROW tree without a permit triggers an appraised-value charge under LMC 13.24.110 plus mitigation. Dead, hazardous, or EAB-infested private trees that are not addressed after Code Enforcement notice can result in municipal nuisance citations and a city-contracted removal billed back to the owner.

This is not one of those rules that cities tend to ignore. Longmont actively enforces its tree removal & heritage trees requirements.

Tree Trimming

Pruning of city-owned trees and trees in the public right-of-way requires a permit from Longmont Forestry Services and must be performed by a City of Longmont Licensed Tree Contractor under LMC Chapter 6.88. Work must follow ANSI A300 standards and ISA Best Management Practices.

Key details: Permit Required: City trees & ROW trees (LMC 13.24). Contractor License: LMC 6.88 — required for aloft work. Insurance Minimum: $1,000,000 general liability. Arborist Requirement: ISA Certified Arborist on staff. Standards: ANSI A300 + ISA BMPs.

Unpermitted pruning, topping or improper cuts on a city or ROW tree can trigger appraisal of damages by the City Forester and mitigation/replacement under LMC 13.24.110. Hiring an unlicensed contractor to perform aloft tree work in Longmont is a violation of LMC Chapter 6.88 against the contractor and may invalidate any work performed.

Weed Ordinances

Longmont follows the Colorado Noxious Weed Act (CRS 35-5.5) and the city's Integrated Weed Management Plan. The state's 98-species Noxious Weed List includes 25 species (List A) requiring complete eradication. Locally, weeds and grasses on private property cannot exceed 12 inches per Longmont Code Enforcement.

Key details: State Law: Colorado Noxious Weed Act (CRS 35-5.5). State List Size: 98 species (25 List A eradicate). Local Height Limit: 12 inches. City Plan: Integrated Weed Management Plan (IPM). Parks Weed Contact: 303-651-8416.

Failure to control state-listed noxious weeds can lead to county/state enforcement orders requiring abatement at the owner's cost. Locally, exceeding 12 inches in height triggers a written abatement notice and, on noncompliance, City-contracted mowing assessed as a property lien plus a municipal citation.

Water Restrictions

As of 2026 Longmont is at a Mild Drought Response Level (Drought Watch) with no mandatory restrictions and no assigned watering days. The City recommends no more than two watering days per week and no irrigation before May 1. An updated 'waste of water' ordinance under LMC Chapter 14.04 took effect in May 2026.

Key details: Current Stage (2026): Mild Drought Response (no mandatory limits). Water Source: St. Vrain Creek / Ralph Price Reservoir. Recommendation: Max 2 days/week; no irrigation before May 1. Waste Ordinance: LMC Ch. 14.04 (updated 4/14/2026). Effective Date: May 2026.

Under updated LMC 14.04 (effective May 2026): broken sprinklers, leaking fixtures, and runoff onto pavement are violations. The City sends a written notice and works with the customer to resolve. Continued noncompliance results in escalating municipal fines and possible water-service action. A formal mandatory restriction stage (Stage 1+) would add assigned watering days enforced under the same chapter.

Rainwater Harvesting

Longmont has no separate local rainwater ordinance. State law (Colorado HB 16-1005, codified at CRS 37-96.5-103) allows residents of single-family homes and multifamily buildings of four units or fewer to collect rainwater from their roof in a maximum of two rain barrels with a combined capacity of 110 gallons. Water must be used on the same property for outdoor uses only.

Key details: Authorizing Law: Colorado HB 16-1005 (CRS 37-96.5-103). Max Barrels: 2 per residence. Max Combined Capacity: 110 gallons. Eligible Residences: Single-family or 4-unit multifamily. Allowed Uses: Outdoor only, same property.

Exceeding two barrels or 110 gallons total, using collected water indoors or for drinking, or collecting from surfaces other than the rooftop violates state law (CRS 37-96.5-103) and can trigger enforcement by the Colorado Division of Water Resources. There is no separate Longmont municipal penalty.

Longmont is more permissive than most cities when it comes to rainwater harvesting. That said, there are still limits.

Native Plants

Effective January 1, 2026, LMC Section 15.05.040 requires drought-tolerant vegetation or native ground cover to be the primary ground cover in landscaped areas, replacing the prior requirement that irrigated turf grass be primary. Decorative (non-functional) turf is now banned in tree lawns, medians, parking-lot strips and transportation corridors.

Key details: Code Section: LMC 15.05.040 (effective 1/1/2026). Primary Ground Cover: Drought-tolerant / native required. Living Plant Minimum: 75% of landscaped area. Banned Locations for Decorative Turf: Tree lawns, medians, parking-lot strips. City Programs: ColoradoScape templates + Slow the Flow audits.

New development and redevelopment that do not comply with LMC 15.05.040 will not pass landscape plan review and cannot receive a certificate of occupancy. Existing properties are not required to retroactively convert, but any new installation must meet the updated standard.

Artificial Turf

Longmont's updated LMC 15.05.040 (effective January 1, 2026) bans artificial turf as a 'non-functional turf' replacement in tree lawns, medians, parking-lot strips, and transportation corridors. Elsewhere on private property, artificial turf is allowed, but Colorado HB 21-1229 prevents HOAs from blocking drought-tolerant landscaping while still permitting HOA regulation of non-vegetative materials.

Key details: Local Code: LMC 15.05.040 (effective 1/1/2026). Banned Areas: Tree lawns, medians, parking-lot strips. Allowed: Private yards (subject to HOA regulation). State HOA Protection: HB 21-1229 + SB 23-178. Living-Plant Minimum: 75% in landscaped areas.

Installing artificial turf in any 'non-functional turf' area listed in LMC 15.05.040 will fail landscape plan review for new or redeveloped sites and will not receive city approval. Disputes between homeowners and HOAs over artificial turf are governed by Colorado HB 21-1229 and SB 23-178 (HOA water-wise landscaping), enforceable in civil court.

The Bottom Line

Longmont's landscaping rules rules are a mixed bag. Some areas are strict, others are relaxed, and the details matter. The best approach is to check the specific rule that applies to your situation rather than assuming Longmont is broadly strict or permissive.

These rules come from Longmont's publicly available municipal code. For complete penalty schedules, exemption details, and answers to common questions, see the individual ordinance pages throughout this guide.