Also known as Michigan holly or black alder, winterberry holly is a slow-growing, medium-sized shrub well known for its bright red berries that persist into spring, creating a striking contrast when sited in front of taller evergreens, walls, or fences. Winterberry’s dark green leaves don’t have the familiar shape of leaves we see on other hollies, so you won’t mind at all when they drop from the shrub to reveal an exuberant display of red berries. The display lasts for weeks or months throughout winter as the birds wait for the fruits to soften. Winterberry is easy to grow in average to wet soils, which makes it ideal for poorly drained areas. It will also grow in drier conditions, though it will not tolerate drought. It may develop chlorosis in alkaline soils, so some acidity is needed. Its rounded, upright form typically grows 6 to 12 feet tall and wide in full or part sun. In moist soils, it spreads by suckering to form colonies. To control growth, remove up to one-third of the branches each year, focusing on the oldest branches and pruning them to the ground. The female plant will only produce fruits if properly fertilized by a nearby male plant, so be sure to site a male within 40 to 50 feet of the females. 
 
Ilex comes from the Celtic word “Ac,” which means “point” and refers to the spines commonly found on the leaves of this genus. However, Ilex verticillata lacks these spines. Verticillata is derived from a Latin word meaning “having whorls,” perhaps referring to the whorls of berries around the stems. Ilex decidua (possumhaw) looks similar to I. verticillata, but its deciduous leaves have crenate, or scalloped, margins and the flowers tend to have fewer petals.  
 
Native habitats include swamps, streams, river banks, bogs, damp thickets, low areas, and pond and lake margins. Great for rain gardens and pond margins. Mass or group in shrub borders, foundations, native plantings, or bird gardens. Makes a dense privacy hedge. It pairs well with American beautyberry, arrowwood viburnum, switchgrass, blue flag iris, and hardy ageratum.
 
Plant Characteristics:
Grows 6-12’ tall and wide.
 
Prefers full sun or part shade. Needs at least 4 hours of sun for best flowering and fruiting.
 
Prefers fairly wet conditions in acidic loam but adapts to other soil types. Doesn’t tolerate alkaline or dry soils. 
 
Greenish-white, ¼” flowers appear June to July. Female flowers have more petals and an ovary. Red, ¼” berries containing 1-2 smooth, bony seeds develop in late summer and fall.
 
Elliptical, sometimes-glossy leaves are 2-3” long with serrated edges. Fall color is usually shades of maroon or yellow. 
 
Smooth, grayish-brown bark covers multiple erect stems up to 2” in diameter.
  
Wildlife Value:
Winterberry is a larval host to 39 species of Lepidoptera, including Henry’s elfin butterfly and pawpaw sphinx moth.  Its berries are eaten in late winter through spring as an emergency food by many species of birds, such as robins, eastern bluebirds, cedar waxwings, woodpeckers, wood thrushes, and gray catbirds.  The flowers attract bumble bees, mining bees, sweat bees, small carpenter bees, and plasterer bees. Rabbits and deer browse on the bark and buds of young winterberry.
 
Medicinal, Edible, and Other Uses:
Native Americans drank a tea made from winterberry bark as a remedy for diarrhea. The bark was used internally to treat fevers, parasites, and liver ailments.  Root decoctions were used to ease hay fever symptoms.  
 
Warning: Winterberry is toxic in large quantities to humans, dogs, cats, and horses.