Security is a popular topic these days, but just talking about it does not necessarily make us more secure. In fact, an awareness of our vulnerability can be an uncomfortable feeling. The landscape is a place where safety, in conjunction with serenity, ought to be assured. We do a lot to make our gardens comfortable and, until recently, many of those landscape design practices were used merely to enhance privacy and aesthetics.

Hedges, fences, screens and walls contribute to a sense of enclosure, of being secured from prying eyes, an ugly view or larger local wildlife. For most people, that's enough, because homes are more likely to be menaced by deer than by human intruders. If your family's personal protection is a concern for you, there are ways you can discourage the attention of vandals and other unwelcome parties.

First, examine the responses of various public bodies to the question of installing security. Keep in mind that there's a good way to install security, with careful planning and appropriate materials, and a bad way, by throwing up any old kind of sturdy, ugly barrier.

Take two examples from downtown Washington: The beautiful rockscape and grove of trees south of the entrance to the East Building of the National Gallery; and the unsightly Jersey barriers and concrete pilings just blocks away at the Capitol.

The question of security and design was the subject of a symposium this summer in Chicago, sponsored by the American Society of Landscape Architects, a 14,200-member professional organization that encourages good design in outdoor spaces, public or private. The meeting, titled "Safe Spaces: Designing for Security and Civic Values," was attended by public officials, law enforcement personnel, security experts and landscape professionals. Although the emphasis was on risk assessment and what devices and materials are available to combat threats, the underlying theme was that security can be repellent without being repulsive.

Or, to quote society Executive Vice President Nancy C. Somerville: "Security design and good design are not mutually exclusive ideals."

Somerville continued in a statement: "Security response plans must be compatible with the practical functionality of where we live, work and travel. They must also respect the beauty and accessibility of our public realm, which represents our nation's values as an open and democratic society." (For more information on abstracts from the symposium, go to the society's Web site, www.asla.org.)

When it comes to home security, most people are interested in protecting their property from vandals, thieves and casual trespassers, not car-bombers. In most cases, plantings will do the job.

When I design for security, I often use a thorny thicket to create an impenetrable barrier. It can provide security at the edge of a property or in a dark corner where one might have occasion to walk at night. If I don't need a tall screen, I keep shrubs pruned to three feet or lower.

On the other hand, large shrub masses should be avoided if you are worried about people hiding in them. While shrubs provide privacy, they have the potential to screen criminal activity and might have to be removed or cut back regularly to secure an area.

If you need foundation plants, keep them low. Shrubs shouldn't cover your windows. This creates the opportunity for an intruder to get in without being seen. Covering your windows from the outside not only keeps others from seeing in, but also keeps you from seeing out. Use dwarf conifers, such as birds nest spruces; low-growing shrubs, such as weeping English yews and Nikko deutzias; or thorny plants that will stay small, such as Dwarf Red Barberry (Berberis thunbergii var. atropurpurea "Bagatelle").

Big thorns can be as scary as big dogs. One bush that people won't hide behind, with its tight mass of thorny leaves, is Rotunda Chinese holly. Crimson pygmy barberry is another small thorny shrub that grows only three to four feet high and wide. Several others guaranteed to hurt an intruder are hardy oranges (Poncirus trifoliata), pyracanthas and wintergreen barberries (Berberis julianae).

If you plant thorny shrubs, don't put them where children will be playing, and be aware that they are trash-catchers. Always wear gloves when you reach in to remove a plastic bag or foam cup that has been snared.

If you don't think plantings are enough to secure your peace of mind, consider walls and fences.

To create the most secure space, you might need complete enclosure and a height of 8 to 10 feet, but many places have fence-height restrictions, so this height isn't always possible. In the French Quarter of New Orleans, for example, some innovative ideas have been used to deter intruders. While the fences meet the more modest height requirements of 6 to 7 feet, tops of gates and walls are adorned with sculptural metal elements that look a lot like spikes -- a definite obstacle.

There are other ways to be creative while protecting your property. For instance, vines can help prevent graffiti artists from expressing themselves on your wall.

Some lines of sight need to be kept open. Where a path or driveway reaches a thoroughfare, you need to be able to see pedestrians on a sidewalk or cars approaching. Place gates and doors so they can be seen from the house, and avoid having an unlocked entry from a deserted alley or pathway.

Hedges, walls and fences can also conceal an intruder. So, consider a picket fence, lattice with large openings, walls with an open pattern or other see-through fencing such as chain link. Chain-link fences, while more or less transparent, aren't the most aesthetically appealing. They are available with plastic coating that can be black (blends with gardens and woodland), brown (against a deck or other wooden structure) or green (with a lawn background). A handsome metal alternative is iron.

If they are well placed, rocks and boulders can be an attractive part of a security system. Don't simply line the property with them. Use a single specimen at a critical spot, or put them in strategic groups and intersperse them with earth berms and plantings.

Another public-security technique that works well around a home is lighting. Ornamental landscape lighting can be used for aesthetics and to keep areas of your property visible at night. An ornamental treatment called "moonlighting" involves hanging fixtures in trees to aim down at the yard. It floods the yard with a soft glow and is both practical and beautiful.

Supplemental security lighting involves strategically placed spotlights and motion sensors. When you install both ornamental and bright security lights, put each system on its own separate circuit. If you add timers, you can give the appearance that your residence is occupied, even when you're away. Bright, high-wattage floodlights have no aesthetic value and should be turned off except when needed for security purposes.

If home security is a major concern, you might want to check with your police. Some departments have crime-stopper programs that offer tips on discouraging theft or vandalism. Some jurisdictions will even send an officer out to evaluate your property for potential threats.

Finally, try to assess your potential risk objectively and respond appropriately. If you live in a gated community, you probably don't need a security fence. If you're an avid gardener, having too many thorny plants may keep even you out of certain parts of the landscape. If you have children, do what you need to make them feel safe without making them feel they're under siege. Consider the aesthetics of any security device. You are the one who will have to live with it.

Joel M. Lerner is president of Environmental Design in Capitol View Park, Md. E-mail or contact him through his Web site, www.gardenlerner.com.

In New Orleans's French Quarter, gates and walls are adorned with metal spikes -- a definite obstacle to intruders.Thorny plants, such as holly, are guaranteed to hurt any potential intruders on your property.