Thorns are sharp, pointed barbs that cover stems or form on branches of plants. Shrubs are herbaceous or woody plants that grow to heights of 1 to 20 feet with deciduous or evergreen foliage. Thorn-bearing shrubs have multiple uses as a method of protecting livestock and crops. Homeowners often plant shrubs with thorns near windows and property lines as a deterrent for burglars. Shrubs with large thorns come in a wide assortment of species.
"Fair Bianca" and "Summer Wind" are cultivars of rose shrubs that have ornamental value in gardens and walkways. "Summer Wind" is a variety of buck rose with large russet-hued thorns with an awl shape. This 5-foot-tall upright shrub has a moderate to vigorous growth pattern. During June, "Summer Wind" flourishes with oval-tipped blossoms with a spicy clove scent and an orange to pink colour. "Fair Bianca" (Rosa ausca) is a perennial rose shrub 3 to 4 feet in height with an upright formation and a spread of 2 feet. The stems have large, narrow sharp thorns. "Fair Bianca" blossoms spring through summer with strongly scented large, showy pure white English roses.
Xylosma (Xylosma congestum) is a 12- to 15-foot-tall large evergreen shrub with large thorns from the Flacourtiaceae plant family. The foliage of the xylosma consists of glossy, ovate leaves with wavy edges. In the early spring, small inconspicuous off-white flowers blossom on the xylosma. This Japanese native develops purple berries in the fall. Wild bougainvillea (Pisonia aculeata) is a thorny compact evergreen shrub belonging to the Nyctaginaceae plant family. The ovate foliage of the wild bougainvillea is a deep green shade. Wild bougainvillea forms small, inconspicuous clusters of greenish-white tinted flowers.
Silver buffaloberry (Shepherdia argentea) is a 15-foot-tall, 8-foot-wide member of the Elaeagnaceae plant family. This deciduous large shrub is a moderately drought tolerant plant with a rounded formation and an annual growth rate of 12 to 18 inches. The foliage of the silver buffaloberry is a bluish-green tone with large thorn-covered twigs. Black hawthorn (Crataegus douglasii) is a deciduous upright shrub with a compact formation. This native to northern and western North America grows to heights of up to 30 feet. The foliage of the black hawthorn has a simple, alternate configuration with 1- to 4-inch-long, egg-shaped leaves. Black hawthorns have scaly thin grey bark and reddish-brown woody stems with large, stiff thorns.
Crown of thorns (Euphorbia Milii) is a woody succulent shrub 1 to 3 feet in height with a spread of 2 to 3 feet. The foliage of the crown of thorns consists of bright green leaves 1 inch in length with stems covered in narrow large thorns. This native to Madagascar blossoms year-round with yellow, gold and orange flowers surrounded by red bracts. Wolfberry (Lycium torreyi) is a thorn-bearing semisucculent small shrub endemic to the United States. This 3-foot-tall shrub has light green leaves that form on thick branches. Greenish-lavender to white flowers develop on the wolfberry along with bright red berries.