Decorating with greenery during the holidays is a time honored tradition. Like the song says, the evergreen most people choose when they “deck the halls” is holly. Holly greenery can sometimes be hard to find and is often expensive. But if your landscape has the space, green thumb gardeners can plant their own holly trees and shrubs for an instant and cheap source of holly boughs.
The genus Ilex (Holly) consists of more than 300 species. There are about 20 American holly species, 120 Oriental species, and nearly 200 English varieties. Among these, their sizes range from 18 inches to more than 50 feet tall. Hollies may have green, blue, or variegated foliage and that foliage may be either evergreen or deciduous. Each holly also has a distinctive shape which may vary from columnar, rounded, pyramidal, or weeping. Such diversity among one genus of plants is why hollies have become popular with landscapers, designers, and home gardeners. Of course we can’t forget the berries. The bright, red berries of hollies add winter interest to gardens and can be food source for birds. They also look great when cut and used in wreaths and flower arrangements during the holidays.
Some of the more common hollies and their use in the landscape include:
- Japanese Hollies (Ilex crenata) – This group of evergreen hollies usually remain small (3 to 10 feet tall) with a similar spread. They have leaves that generally look more like boxwood than holly as they lack spines on the leaves. They tolerate severe pruning, which makes them an excellent choice for a hedge, and they have black berries. Among these dense shrubs the most common selections include ‘Compacta’, ‘Helleri’, ‘Microphylla’ and ‘Rependens’.
- Chinese Hollies (Ilex cornuta) – These medium growing hollies (10 to 20 feet tall) produce large, spiny, dark green leaves. They are also one of the few hollies that can produce berries without pollination. The ‘Burfordii’ is a popular medium growing tree (20 feet) which attracts birds to its heavy fruit set. The ‘Dwarf Burfordii’ does not set as heavily but grows only half as tall. ‘Berries Jubilee’ is a rounded 10 foot tall tree that produces a heavy crop of bright, red berries.
- American Holly (Ilex opaca) – The tallest of all hollies (50 feet) is a native holly. It has large, spiny green leaves and bright, red berries. Many cultivars exist, including ‘Jersey Delight’, ‘Merry Christmas’, and ‘Yellow Berry’ which has bright, yellow berries.
- English Holly (Ilex aquifolium) – One of the few evergreens with cultivars of variegated white and green foliage. English hollies are attractive; however their slow growth rate and poor heat and drought tolerance make them less popular in the south.
- Yaupon Holly (Ilex vomitoria) – This holly is native to the eastern U.S. It may grow to 15 feet tall and the females produce small, red berries. Two popular cultivars are ‘Dwarf Yaupon Holly’ which only grows to 5 feet and ‘Pendual’ which has a weeping habit.
- Possumhaw Holly (Ilex deciduas) – This deciduous holly may not add much foliage to decorations but the masses of berries that are left on the branches add a brilliant show both in the landscape and indoors. This small tree may grow to 10 feet tall
- Winterberry (Ilex verticillata) – Another deciduous holly that produces enormous crops of bright, red berries that persist through winter. This small tree does well in boggy soils.
- Meserve Holly (Ilex meserveae) – This small growing (7 feet tall) group of shrub hollies includes the “blue” hollies, referring to the blue-green winter foliage color. Although they are very cold hardy they often struggle in our hot, dry summers.
Growing hollies is fairly simple. Most hollies require well-drained soil that is rich in organic matter and slightly acid. Japanese Hollies are intolerant of poorly drained soils. Hollies can grow in sun or shade but produce the best berries when planted in full sun. Some hollies are self-fertilizing, but many require a male holly nearby for berry production. A reputable nursery can tell you which holly pairs are needed for fertilization. Maintenance is usually limited to pruning of vigorous cultivars and problems can be avoided by selecting a species that meets your height requirement in the landscape before planting. Containerized and balled-and-burlapped trees can be planted now so long as the ground is not frozen. Even during cold weather it is important that your newly planted holly receives water during dry periods.
There are few insect problems encountered on holly. Occasionally leaf miners, Japanese wax scale, or red mites may be found. The biggest problem most holly owners face is lack of berry production. Provided your holly is either self-pollinating or has the correct mate nearby, the most likely reasons are poor pollination (male and females trees are too far apart or insect pollinators were limited by the weather); young, immature plants; high nitrogen levels in the soil; hot, dry summers which may cause the plant to abort the fruit; it is a dwarf variety which does not produce abundant fruit; or a late spring frost killed or injured the flowers.
Submitted by Kelly Jackson, Agent for Horticulture, Christian Co. Cooperative Extension