When the English Channel flooded some 8,000 years ago to separate the British Isles from Europe, plants stopped migrating naturally between the two land masses. The plants then growing in the United Kingdom's soil are its true native plants, according to the Lingfield Nature Reserves. Many of them are native shrubs now growing as ornamentals in U.K. home gardens, and in the hedgerows lining the country's roads and rural lanes.
A broadleaf evergreen, English holly (Ilex aquifollium) is easily recognizable from its spiny, glossy deep green leaves. Small, white summer flowers on mature wild plants--those more than 20 years old--have bright red autumn berries. Male and female plants are necessary for pollination and fruit.
This holly shrub is a common sight in oak woods across the United Kingdom, and a popular ornamental shrub for home gardens. U.K. gardeners can choose English holly cultivars of different sizes, with variegated foliage or berry colors other than red, according to the Royal Forestry Society. English holly performs best in full sun with afternoon shade and well-drained soil.
A dense, spiny shrub, sea buckthorn (Hippophae rhamnoides) brings four seasons of interest to U.K. coastal gardens. It has graceful, silvery leaves, white March and April flowers, and brilliant orange fall and winter berries. Up to 20 feet high and wide, it thrives along seacoasts throughout the United Kingdom where it handles handles sun, shade and sandy soils from dry to saturated, according to the Deeproot Plantbase website. It's also hardy to USDA plant hardiness zone 3, with winter temperatures between minus 30 and minus 40 degrees Fahrenheit. Like those of English holly, sea buckthorn's female plants need male pollinators in order to fruit.
Southern and central England's oldest forests are home to Midland thorn (Cratageus laevigata), a deciduous broadleaf shrub or small tree. This up-to-30-foot, brown-barked plant is unmistakable for the carrion-like odor of its white, spring flower clusters. Ornamental berries arrive in late summer, becoming bright red by October or November. Midland thorn frequently grows in hedgerows with common hawthorn, according to the UK Wildlife Natural History Website. Although the two plants are related, common hawthorn's flowers are much more pleasantly scented.
Blackthorn (Prunus spinosa) blooms early enough in spring that the arrival of its white March flowers is sometimes called "blackthorn winter," according to the Natural England website. A spreading, heavily-branched shrub, it can reach 13 feet high. It grows along woodland edges and in scrublands throughout England and Ireland, and in eastern Scotland. Only acidic soil deters it. The thorny shrub's most significant feature may be its blue-black, plum-like fall fruits. Harvested after the first frost has sweetened them, these "sloes" are the main ingredient in sloe gin.