While landscaping and plant growth can contribute to the beauty of a residence, multi-residential units, or business if not carefully controlled and designed, they can also provide hiding places for criminals.
Ground Cover Plants
As an alternative to shrubbery use ground cover plants, perennials and/or annuals for areas within six feet of the edge of walkways, parking lots and building entryways or other areas requiring visual surveillance.
The height or ground cover plants should not exceed two feet at maturity. Plants with thin stalks over two feet high that still allow for good visual surveillance may be used in these areas.
In addition to ground covers and pruned trees, shrubs may be used between six and 12 feet from the edge of walkways, parking lots and building entryways.
The height of landscape shrubbery should not exceed three feet at maturity.
Barrier plants have thorns or needles and often a dense structure. They can be used below and near windows to discourage access. They can also be used adjacent to fences or building walls. Among such popularly-used barrier plants are Pyracanthia, Agrave, Barberry, Natal Plum, Yucca, Hedgehog or Porcupine Holly. Even if placed below windows, these plants should be trimmed below the height of the windowsills.
Since the purpose of barrier plants is to discourage pedestrian access, it may be acceptable for them to exceed three feet in height in some applications.
Trees should be located or trimmed so as not to serve as a climbing aid to upper levels of homes or buildings or as a climbing aid over fencing or perimeter barriers. Trees should also not be placed where their foliage obscures roadway, walkway, or parking lot security lighting. If trees are located in these areas, they should be thinned and trimmed on a regular basis.
Trees should be pruned so that their lowest foliage is no less than seven feet from the ground surface.
Landscape rocks can be used as an effective alternative to ground cover or shrubs. Small landscape rock can be used under windows or near entryways to create noise when stepped on by a prowler.
Source: American Crime Prevention Institute