Montgomery County, MD Invasive Plant Rules: Prohibited Species (2026)
Key Facts
- Governing list
- Maryland Invasive Species Council
- Applies to
- landscaping required under Ch. 59
- Enforcement lever
- certificate-of-occupancy hold
- Plan preparer required
- licensed landscape architect
- Not covered
- Rockville, Gaithersburg, Poolesville, others
Summary
Montgomery County's zoning code (Ch. 59, § 59.6.4.3.A.6) bars any species on the Maryland Invasive Species Council's invasive list from required landscaping plans, enforced by withholding the final certificate of occupancy until compliant plants are installed.
Species included on the Maryland Invasive Species Council's list of invasive aquatic or terrestrial plants must not be used for landscaping.
B. Landscaping Elements
1. Plant Material
a. Any landscaping must be installed under the accepted standards of the American Standard for Nursery Stock, latest edition, as published by the American Association of Nurserymen.
b. Plant material must be true to name, variety, and size and must satisfy all applicable provisions of the American Standards for Nursery Stock, latest edition.
c. Mature plant size is based on the Manual of Woody Landscape Plants, Stipes Publishing, latest edition.
2. Canopy Trees
a. Defined A canopy tree is a large deciduous tree, typically 40 to 70 feet tall at maturity, with a minimum spread (canopy) of 30 feet. A canopy tree typically has only a single trunk.
b. Size at Time of Planting Any canopy tree within an open space area, screening area, or surface parking lot must have a minimum caliper of 2 inches or a minimum height of 14 feet when planted.
3. Understory Trees
a. Defined An understory tree is a small deciduous tree, typically less than 30 feet tall at maturity. Many understory trees have multiple trunks.
b. Size at Time of Planting
i. Any single trunk understory tree located in an open space area, screening area, or surface parking lot must have a minimum caliper of 1.5 inches or a minimum height of 10 feet when planted.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: 2026 S-90: Montgomery County Code contains legislation effective through May 7, 2026 | Zoning Updated Effective: April 13, 2026 | COMCOR Regulations effective as of July 1, 2026).
Full Breakdown
Montgomery County's zoning code bars landscape plans from using any species on the Maryland Invasive Species Council's list of invasive aquatic or terrestrial plants. The rule sits in the Chapter 59 general landscaping standards that apply whenever a site plan, subdivision, or building permit triggers required landscaping: new construction, parking lots, and multi-unit development. A licensed landscape architect must prepare the planting plan, and DPS will not issue a final certificate of occupancy until the installed plant material satisfies these standards. The rule does not reach existing yards planted before landscaping was triggered, and it does not apply inside Rockville, Gaithersburg, Poolesville, Brookeville, Laytonsville, Barnesville, or Washington Grove, which administer their own zoning codes.
Violations & Fines
DPS withholds the final certificate of occupancy until required landscaping satisfies Division 6.4's standards, including the invasive-species exclusion, so noncompliant plantings must be replaced before occupancy is granted.
Frequently Asked Questions
Does this ban apply to my existing backyard garden?
Which plants are actually banned?
Does this rule reach Rockville or Gaithersburg?
Sources & Official References
Other rules in Montgomery County
Compare Montgomery County to another location·View the Maryland invasive plant rules overview
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