Deterring home invasions are one of the many features that landscapes can provide when being designed. Using plants that have thorns or cause irritation can help deter would-be-intruders.
Washington Hawthorne
Washington Hawthorne Having a shade tree is ideal for homeowners, but having a thorny shade tree that prevents entrance into second stories is even better. Washington Hawthorne is a tree that meets that requirement. Don't let the thorny nature of this tree deter you though, its brilliant white flowers in the spring and delicate orange fruits speak for themselves. Best of all, this tree is resistant to fire blight, a disease that is known to affect many hawthorne trees. Best planted in zones 4-8, it will thrive in any soil, reaching 25-30 feet tall and 20-25 feet wide with a very round, dense shape.
Black Locust
A large, deciduous tree that makes it difficult to climb due to the thorns. There are thornless varieties available, but when trying to deter home invasions, thorns are the perfect defense! Reaching over 70 feet into the air at maturity, this tree has beautiful white flowers that attract pollinators. Come fall, dark purple-brown pods develop and are favored by many bird species. The green foliage turns to a clear yellow, before dropping for the season. One of the hardiest trees available, black locust thrives in zones 4-9, and will adapt to most soil types. Between the birds that may become territorial in the canopy and the thorns that develop along the branches, black locust is a great home-invasion deterrent tree, especially if you have multiple stories.
Carissa Holly
Carissa Holly For plantings near windows on the first story, "Carissa" Holly " Ilex cornuta 'Carissa' " is a wonderful choice. At first glance, it seems innocuous. But upon further inspection, it's obvious that this plant has protection in mind, spines at the tip of the leaves have a bite. Evergreen through all the seasons, it makes an ideal backdrop for other brightly colored flowers to be planted in front. It stays round and fairly low, reaching a mature size of 3 feet tall and 3 ' 4 feet wide. Best planted in zones 6-9, this plant should be placed in front of a window for an optimal deterrent.
Rosy Glow Barberry
Rosy Glow Barberry Another under-the-window plant to deter home invaders is Rosy Glow Barberry is a small compact shrub (3 feet at maturity) that looks fantastic as a hedge. Like the name suggests, the ruby-tinted leaves make a statement when planted with other plants. The color only intensifies in the fall, before falling and leaving a thorny mass of branches. Best planted in zones 4-8, and tolerant of many soils, this slow-growing shrub will protect and deter from potential invaders.
Twist of Pink Oleander
Twist of Pink Oleander When stems are broken off, Twist of Pink Oleander releases a milky substance known to irritate skin and, in severe cases, cause blistering. Reaching 6-8 feet tall, its uses are limited with its size, but it works amazingly well as a hedge, especially in dry, arid environments. The variegated evergreen leaves persist all year-round, and bright pink flowers bloom in the summer, contrasting with other landscape beauties. A relatively low-maintenance plant, Twist of Pink Oleander is another tool at your disposal for home-invasion peace of mind, especially since it thrives in zones 8-10 in most soil types.
Rugosa Rose
Rugosa Rose Finally, we come to one of the prettiest home-deterrent plants available: roses. Known for their thorns and their prolific flowering, there is a rose for almost every need. Height and flower color are species dependent, but choosing something like Rugosa rose will be key to helping deter would-be home invaders with their prolific thorns. As a bonus, you get to enjoy the simple blooms throughout the growing season. Ranging in hardiness from zone 2 to zone 8, many of the rugosa roses are extremely reliable and tolerant of many soil types. These six plants can help deter would-be home-invaders from entering your house with thorns and irritants. Even though plants are no substitute for other good practices (locking your doors and other techniques), they can be one tool in the toolbox for house safety.Washington Hawthorne
