Defensive Plants

Defensive plants are not simpering wallflowers.

People have used defensive plants to protect their crops, livestock, and homes for thousands of years. Wicked thorns and dense thickets have deterred a variety of predators and thieves. And some defensive plants offer the bonus of an edible crop!

Porcupine tomato (Frank Vincentz) CC BY-SA 3.0

What looks like an easy back fence to hop becomes much more of a challenge when it supports thorny blackberries or a row of prickly pear cacti. Most thieves and troublemakers will look elsewhere for easier pickings. And if they decide to hop anyway, their howls of pain will give you plenty of time to call the police

Blackberries (Kate Russell)

The best places for defensive plants are along fences, under windows, and around sheds and other outbuildings. Keep mature plant sizes in mind when placing defensive plants, and ensure they will not block your escape should the need arise.

Prickly pear (Stan Shebs) CC BY-SA 3.0

Before adding defensive plants to your landscape, use the information below to ensure they are suited to your Hardiness Zone and local microclimate. Most of these plants prefer full sun and well-draining soil unless noted otherwise. [Note: the abbreviation "spp." indicates several species.]

• Barberry spp. (Berberis), Zones 4-12; partial to full sun; evergreen and deciduous shrubs; some species are invasive, so check before planting.
• Barrel cactus (Echinocactus and Ferrocactus spp.), Zones 9-11; 3 feet tall and 3 feet wide; slow growing.
• Blackberry (Rubus fruticosus), Zones 3-11; 5 feet tall and 8 feet wide; Upright and trailing varieties; also thornless varieties.
• Blackthorn (Prunus spinosa), Zones 4-8; partial to full sun; moist soil; deciduous shrub; 10 feet tall; berries used to make sloe gin.
• Bougainvillea spp. (Bougainvillea spp.), Zones 9-12; vines and shrubs.
• California fuchsia (Ribes speciosum), Zones 7-12; shade to partial shade; deciduous shrub; 8 feet tall.​
• Century plant (Agave americana), Zones 8-11; succulent.
• Chinese jujube (Ziziphus jujuba), Zones 5-11; up to 40 feet tall; thornless varieties available.
• Cholla cactus (Cylindropuntia spp.), Zones 8-12, dry soil, succulent, various sizes.
• Crown of thorns (Euphorbia milii), Zones 8-12; evergreen succulent, 6 feet tall; sap is toxic.
• Devil's walkingstick (Aralia spinosa), Zones 4-9; full or partial sun; deciduous tree; 20 feet tall; can become invasive.
• Giant rhubarb (Gunnera manicata), Zones 7-10; moist soil; herbaceous, rhizomatous perennial; 8 feet tall and 12 feet wide; sap, stalks, and leaves are toxic.
• Hardy orange (Poncirus trifoliata), Zones 5-12; deciduous shrub or small tree; 20 feet tall; stems stay green in winter; fruit is edible but very sour.
• Hawthorn spp. (Crataegus spp.), Zones 4-8; deciduous shrub; sizes vary; tart fruits used to make jellies and jams.
• Holly (Ilex aquifolium), Zones 5-9; full sun to partial shade; any soil; evergreen shrub; 12 feet tall; can become invasive.
• Honey locust (Gleditsia triacanthos), Zones 3-9; deciduous tree, 90 feet tall; fast-growing.
• Japanese quince (Chaenomeles speciosa), Zones 5-9; deciduous shrub; edible fruit is tart.
• Mesquite spp. (Prosposis spp.), Zones 7-9; arid soil; deciduous tree; 30 feet tall; can become invasive; avoid non-native species.
• Ocotillo spp. (Fouquieria spp.), Zones 7-12; semi-succulent; 20 feet tall and 15 feet wide.
• Oregon grape (Mahonia aquifolium), Zones 5-8; partial to full shade; evergreen shrub; 6 feet tall and 5 feet wide; unrelated to grapes, but the fruits are edible.
• Porcupine tomato (Solanum pyracanthos), Zones 9-11; evergreen shrub; 4 feet tall and 3 feet wide; fast-growing.
• Prickly pear spp. (Opuntia spp.), Zones 4-12; succulent; up to 10 feet tall; edible fruit.
• Pyracantha spp. (Pyracantha spp.), Zones 5-9; partial to full sun; evergreen shrub; 12 feet tall and 12 feet wide.

Honey locust thorns (Greg Hume) CC BY-SA 3.0

Add an extra layer of protection to your property with any of these plants.