The American holly shrub has sharp leaves and red berries.

Looking to add a plant that provides color during winter? Searching for a native shrub or tree that will attract birds and other wildlife? Planning to plant a living privacy screen?

If so, the American holly (Ilex opaca) is a species to consider adding to your landscape.

Long considered a symbol of the Christmas season, American holly works well as a year-round addition to the landscape as a native evergreen. The species can be grown as a shrub, hedge or tree.

If allowed to grow naturally, American holly forms a densely branched pyramid-shaped tree capable of reaching 50 feet in height and 20 to 40 feet in diameter. With adequate space, American holly would create an impressive focal point in the landscape. However, because it responds well to pruning, it is more commonly grown as a shrub or hedge.

The holly's dense leaves are very stiff and leathery with sharp spines. Flowers emerge in the spring along the branches. They are small, dull white, and lightly aromatic making them attractive to honey bees and other pollinators.Holly is a dioecious plant, meaning that the male and female flowers are borne on separate plants. To successfully produce berries, plant multiples of holly shrubs. To optimize berry production, plants should be sited within 40 feet of each other. One male is capable of fertilizing three females.

The requirement of multiple individuals also adds to the ease for growing as a hedge. Because there are many cultivars of American holly, make certain to choose ones that bloom at the same time for proper pollination. Green berries in summer turn bright red in the fall.Berries are toxic to humans but are an important food source for birds including wild turkeys, cedar waxwings, mourning doves, American goldfinches, northern bobwhite, northern cardinals, and several thrush species, including American robins.The American holly grows readily and once established does not require much care.To use hollies in your landscape, purchase balled and burlapped or container grown plants. Bare root or plants dug in the wild do not transplant well. Plant in the spring or early fall.

Hollies tolerate a wide variety of soils including sand, loam or clay. Soils should be slightly acidic (pH range 3.5-6.0).The location should be sunny to partly shady and moist but well-drained. Hollies do not tolerate continuously saturated soil conditions. They will tolerate dry soil; however, during very dry conditions, supplemental watering is necessary. If the site is too shady, fewer flowers (and berries) are produced and the branches form a more open growth habit.In southwestern Pennsylvania, the site should also offer protection from winter's cold north winds that can dry out leaves and kill twigs. Winter drying of leaves and twigs will stress the holly but not kill it; new leaves will form in the spring.In spring, apply an acid fertilizer. The rate of growth is considered medium to slow at 12 to 24 inches a year under ideal conditions.As a native species, American holly are not vulnerable to many diseases or pests.They can be prone to leaf drop or sun scorch in extreme heat, and leaves can turn yellow if the soil is too alkaline. Root rot can become a problem if the site does not drain well.American holly is also susceptible to fungal and insect infestations though most will not kill the plant. Leaf miners, scale insects, spider mites and whiteflies can create infestations; of these, leaf miners and scale insects are the most destructive. Horticultural oil will generally control most insect problems.If natural food is scarce in winter, deer will resort to feeding on holly; however, the prickly leaves should deter heavy browsing.There are many cultivars including dwarf ('Maryland Dwarf') and yellow-berried varieties ('Goldy').Recently, some growers have begun placing a male and a female plant in one pot to simplify the need for selecting both sexes for proper pollination and berry production. American holly are available for purchase at most nurseries.Look for cut holly branches when purchasing holiday greens. Decorate with holly in outdoor containers and wreaths to avoid exposing children and pets to the poisonous berries.If you have questions about native shrubs for pollinators, including American holly, call the Butler County Master Gardener Garden Hotline at 724-287 4761, ext. 7, or email the Master Gardeners at butlermg@psu.edu.Mary Alice Koeneke is a Penn State Extension Butler County Master Gardener.

Mary Alice Koeneke is a retired biologist who enjoys birdwatching and gardening. As a Penn State Extension Master Gardener Butler County (Class of 2016), she is especially interested in gardening for birds, pollinators, and wildlife using native plants.

holly leaf

Holly flowers are loaded with pollen, making them attractive to honey bees and other pollinators.

Holly berries are an important food source for birds but are poisonous to humans. At right, the American holly shrub shows its sharp leaves and red berries.Submitted photos