Landscaping for Security: Shrub Heights, Canopy Clearance & Sightlines

The 2-foot / 6-foot sightline rule

CPTED practitioners commonly reference keeping shrubs and low plantings trimmed to roughly 2 feet or less, and tree canopies limbed up to roughly 6 feet or more, so that a person standing has an unobstructed sightline through the space between those heights. This is sometimes called the '2 and 6' rule. It is a design heuristic, not a fire code or state statute, but many municipal landscape ordinances and HOA design guidelines incorporate a version of it.

The goal is natural surveillance: residents, passersby, and patrol officers should be able to see a person standing near a building, mailbox cluster, or parked car from a reasonable distance, and that person should be visible from inside nearby units or offices. Dense hedges along a fence line, overgrown foundation plantings under windows, or a tree canopy that has grown down to head height near a walkway all defeat that visibility even if the landscaping looks well maintained otherwise.

Sightline planning also matters at property entrances and along pedestrian routes between parking and buildings — routes that are convenient shortcuts are also the routes most people actually walk, so they deserve priority when trimming schedules are decided.

Common landscaping problem spots

• Foundation shrubs grown tall enough to hide someone crouched below a ground-floor window.
• Untrimmed hedges along a perimeter fence that block sightlines from the street or from patrol vehicles.
• Tree canopies drooping over walkway lighting, cutting the effective light coverage without anyone noticing during the day.
• Overgrowth around dumpster enclosures, transformer pads, and utility areas that are already low-traffic and low-visibility.
• Vegetation encroaching on signage or address numbers, slowing emergency response.

Landscaping reference points

Pairing landscaping with patrol observation

Landscaping crews are typically on-site on a schedule of weeks, not days, so overgrowth can quietly creep back into concealment range between visits. A patrol officer walking or driving a property regularly is often the first to notice a hedge line closing in on a sightline, a canopy dropping onto a light fixture, or new growth blocking a camera's field of view — and can flag it for the landscaping vendor before it becomes a security gap rather than after an incident makes it obvious.