Since plants, trees and other landscaping elements around your home can play an important role in home security, you may be overlooking simple but effective ways to discourage unwanted intruders.
Area landscape architects say that with a little thought and planning, the landscape for your home can create passive security without sacrificing aesthetics. This won't make your home impenetrable, they say, but it will increase the chances that would-be burglars or muggers will pass up your home for an easier target.
A security-enhancing landscape design uses plant material to block potential points of entry for homes and yards. Thorny or prickly plants create barriers along fences, property lines or under windows and, if placed close to a wall or fence, are difficult to hide behind.
Lighting, preferably low-voltage, is used to eliminate shadows that could hide intruders. At the same time, it can enhance your landscape.
"If you're going to design a landscape or renovate a landscape, take a look at security as one of the major items that you want as part of the landscaping," says Bruce Wegner, a landscape architect and manager of parks and recreation for the city of San Clemente. "A little bit of design can provide a lot of security.
"Generally, someone that's going to try and illegally enter your house is probably going to look for a simple way of doing it and if you make it difficult for them, then chances of them wanting to enter are going to be less."
Wegner developed his ideas about security and landscaping when he worked for the city of Ontario. The Police Department asked him to help design a program to encourage people to use landscape design to enhance security.
The goal, he says, was "a nice landscape atmosphere that provides for safety as well as aesthetics. You try to minimize the potential points of entry for the person that might want to enter without your consent."
And the most likely points of access, he says, are usually around windows or over fences.
"I think (security) is a very important aspect" of landscape design, says Pamela Hayes, a landscape architect and the owner of Canyon Gardens Nursery in Anaheim Hills.
What should a homeowner plant to prevent people from climbing over a fence?
Climbing, thorny vines like bougainvillea or cat's claw work well on block walls and other fences that don't need much maintenance, Wegner says. The vines cling to the fences and their thorny structures provide a barrier like barbed wire. Even if the fence is only 4 feet high, it will still be difficult to climb when it's covered with a thorny vine.
A vine won't work if a fence is going to need paint or other maintenance. In this case, plant a thorny hedge along either side of the fence, Wegner says. "If you plant it outside, it's going to deter the person from getting in in the first place."
Hayes suggests planting one of the low-growing varieties of thorny natal plum as a ground cover in front of a fence, making it painful for an intruder to walk through.
Prickly low-growing shrubs planted under windows also deter unwelcomed visitors. Wegner suggests using Dwarf varieties of thorny shrubs against the window to prevent anyone getting behind them. Keep the shrub trimmed so you can still see out the window. If the shrub is low enough, he says, it's still possible for the homeowner to get in and wash the window.
A taller, thorny shrub can be used to screen a window for privacy, Wegner says.
"The disadvantage (of the taller shrubs) is that if you have them in front of windows, it makes it difficult to get in there and paint or to do maintenance," Wegner says. But there is only an occasional need for this activity and "if you're concerned about security, the security far outweighs the disadvantages."
Secluded front yards may be attractive, but they are security hazards.
Front yards, Wegner says, should have an open line of sight. That means anyone walking from a driveway to the front or side of the house should be clearly visible, and occupants shouldn't walk past areas where someone could be hiding.
"When you approach your house from the street," Hayes says, "you want to be able to see that front door and have nothing obstructing it."
Trees near a walkway may cast a shadow where an intruder could lurk, and large trees close to a house can be used to climb to a second-story window, according to Daphne Osburn, a landscape contractor with Tokay Nursery in Brea.
Some homeowners are more concerned with keeping nuisance traffic out of their yard than with dangerous intruders, Osburn says.
"People seem to be real concerned with privacy of their yard, " Osburn says. She says clients frequently ask her how to keep children and trespassers out of their yard.
Though it won't result in a "good-neighbor award," she suggests using a thorny or prickly ground cover or a hedge of prickly shrubs as a barrier. A hedge of low-growing junipers or natal plums 2 to 4 feet high and at least 2 feet thick can't easily be stepped over, she says.