Holly - U of I Extension

News Release


This article was originally published on November 15, 2010 and expired on March 1, 2011. It is provided here for archival purposes and may contain dated information.

Evergreens add excitement to an otherwise dull winter landscape, said a University of Illinois Extension horticulture educator.

"My favorite winter scene is branches of bright green holly leaves with sparkling red berries against fresh white winter snow," said Jennifer Fishburn.

"Holly is the common name for the genus Ilex which has more than 400 species including both evergreen and deciduous leaved species. Holly plants are a great addition to the landscape but careful consideration must be given to the planting location. The ultimate size and shape of a mature plant is an important consideration."

Plants need ample space to grow. Evergreen hollies need to be planted in partial shade protected from winter sun and wind. They prefer a moist, organic, well drained soil. While most hollies will tolerate alkaline soil, they prefer an acidic soil. Select cultivars which are hardy in zone five. Be sure plants receive ample moisture during dry periods, especially going into the winter season.

"Several holly species will provide colorful fruit for three to six months of the year ," she said "Fruit persistence depends on the bird and squirrel population in an area. Plants with yellow berries are often ignored by birds or are eaten after red fruits are gone."

Holly plants are dioecious, meaning both male and female plants are needed to ensure fruit production. Only the female produces fruit.

"It is important to have male and female plant that are closely related and flower at the same time," said Fishburn. "How do you know the sex of a plant? Male and female flowers have different parts. For some of us, this may be a little difficult to see, so we must rely upon retailers to correctly mark the plants. Most cultivars have sex appropriate names such as 'China Boy'."

Mature plants can be kept at a manageable size and shape by pruning them in late fall or early winter. Prune hollies after they have been established for several years as new plants resent pruning. An added bonus of pruning is to collect the branches and use them as holiday decorations. Holly branches covered with berries look great in an outdoor container or on a fireplace mantel.

"One of the better suited hollies for our landscape conditions is common winterberry, Ilex verticillata," she said "Winterberry is a deciduous holly which is hardy to zone three.

"Another bonus is this native plant is fairly pest and disease resistant. The leaves, which are rounded, will remain on the plant into late fall. Red berries begin their display in September and can last for several months."

Cultivars vary in height from five to 10 feet. This species is a good selection for shrub borders or screening. Female plant selections with red fruit include 'Red Sprite', and Winter Red®. 'Red Sprite' is a shorter cultivar growing 3 to 5 feet tall. Winter Red® can get eight to nine feet tall and wide. A good male pollinator is 'Jim Dandy' a dwarf, slow grower.

Blue holly, Ilex x meserveae, is a blue-green broadleaf evergreen holly growing eight to 15 feet tall. Lady selections for this group include: Blue Princess®, Blue Maid® and Golden Girl®.

"As the name implies, Golden Girl® produces vibrant yellow fruit," said Fishburn. "Male pollinators for these ladies include: Blue Stallion® and Blue Prince®."

Another red fruiting hybrid holly is Ilex rugosa x cornuta. Selections include China Boy® and China Girl®. They are more heat and cold tolerant than blue hollies.

Inkberry holly, Ilex glabra, produces a black fruit. The dark green leaves resemble boxwood leaves. 'Compacta' is a common selection that grows up to six feet tall and about the same spread.

"Spark up your winter landscape with one of these great holly selections," she recommended.

Source: Jennifer Fishburn, Extension Educator, Horticulture, fishburn@illinois.edu

Pull date: March 1, 2011