Variety of Plants Lend Selves to Security Role

Now may be a great time to install security-oriented plants and not just because of growing concerns about crime.

“With current drought conditions, lawns are going to be dwindling,” landscape architect Patrick Caughey said. “This is an opportunity to put in low-growing shrubs, junipers and other drought-tolerant plants that can also control access. As we lessen lawn space, people have to figure out what to put in its place.”

Bougainvillea, pyracantha and carissa are the most frequently recommended plants for defensive gardening, but area nurseries, landscapers and other experts offered these possibilities:

Acacia--Several of the 20 or so evergreen shrub or tree species suitable for Southern California have thorns, spines or multi-stemmed mass useful as barriers. Drought tolerance varies.

Agaves--The huge varieties (i.e., century plant) require lots of space, cannot be easily removed and have vicious spines. Spectacular and drought tolerant in the right setting.

Araucaria--Certain of these conifers attain imposing height and bulk with stiff, sharp leaves and intertwining branches. Includes the unusual “monkey puzzle” and “bunya-bunya.” Ask about growth habits and needs.

Asparagus (ornamental)--Certain varieties, notably sickle thorn asparagus and fern asparagus, have erect, thorny stems climbing from 10 to 20 feet in a potentially unruly mass. Some drought tolerance.

Bamboo--Another plant the experts say should be selected carefully because of its impenetrable mass and potential to become invasive. Clumping varieties are preferable. Drought tolerant.

Barberry--Holly-like varieties, principally the Darwin (Berberis darwinii), are recommended for prickly branches and/or leaves, as well as potential mass. Generally tough and drought tolerant.

Berries--Many berry plants have thorns and rambling growth habits that make them impossible to walk through. The disadvantage is their water dependency.

Cactus--There are many drought-tolerant, hardy, thorny varieties from which to choose, depending on growing conditions.

Citrus--Most often mentioned are thorny citrus varieties including lemons and Mexican lime. The downside may be their need for regular watering.

Coral tree (Erythrina)-- Includes extremely thorny varieties of trees or shrubs. Can be drought-tolerant if so trained. Requires certain growing conditions.

Cycad--These fern- or palm-like primitive plants related to conifers are likely to best serve as container plants due to their particular growth requirements and collector’s value.

Cypress--Sticky leaves, dense growth and drought tolerance are among most cypress qualities. Certain regional cypress (i.e. Tecate) are losing native habitat, so planting helps species survive.

Floss silk tree (Chorisia)-- Showy flowers and genteel appearance belie assemblage of thorny spines along the tree trunk. Has moderate water needs.

Flowering quince (Chaenomeles)-- These deciduous shrubs require moderate watering. Most are thorny. Planted in the right conditions (depending on variety), they are showy and durable.

Hakea--Most recommended variety is sweet hakea (H. Suaveolens) with its prickly, stiff, segmented leaves, considerable mass and drought tolerance. Features fragrant flowers in fall and winter.

Hawthorn (Crataegus)-- Related to roses, these thorny deciduous trees offer drought tolerance, pretty flowers and colorful fruit favored by birds.

Holly (Ilex) --Varieties of these evergreen trees and shrubs have sharp-edged leaves. Generally requires consistent watering.

Junipers--These shrubby evergreens vary considerably in height and habit. Ground-hugging species can be difficult to walk through; taller types provide barriers. Basically drought-tolerant.

Mahonia--These adaptable, drought-resistant and attractive evergreen shrubs have sharp leaves and fruits favored by birds. Includes one endangered native now cultivated for garden use (M. nevinii).

Manzanote (Olmediella betschlerana)-- Sharp, holly-like leaves are prominent feature of this evergreen tree or shrub. Adaptable, but it needs extra watering in hotter areas.

Melaleuca--Most recommended variety is drooping melaleuca (M. armillaris) , which can be trained to serve as a shrub or small tree. Has extremely prickly leaves.

Ocotillo (Fouquieria) --Stunning spiked deciduous shrub happiest in desert regions. Individual stems grow upward from central base to 25 feet. Stems contain extreme thorns.

Osmanthus--Most recommended is holly-leaf (O. ilicifolius) variety with its toothed leaves, dense mass and fragrant white flowers. Evergreen shrub is drought-tolerant once fully established.

Palms--Many varieties, dwarf and tree-sized, feature spiny leaves, abrasive trunks and bulky mass. They have varying drought tolerance and growing needs.

Palo verde (Cercidium)-- Generally deciduous, these feathery leaved, delicate looking trees have not-so-delicate thorns. Drought tolerant and hardy under the right growing conditions.

Pampas grass (Cortaderia selloana)-- Plant this drought-tolerant, towering tufted windbreak with a lot of forethought because of its sheer mass and invincibility. Its grass blades are swordlike.

Rose--There are many thorny varieties. Compare growing habits, hardiness and potential water needs.

Xylosma congestum--Some are spiny and can spread to 30 feet, earning utilization as both shrubs and small trees. Evergreen or deciduous, they are considered hardy but need watering to look best.

Yucca--All have tough, long, pointed leaves. Hardiness varies, but many types are drought-tolerant. Two common choices are Spanish bayonet (Y. aloifolia) and Spanish dagger (Y. gloriosa).