Holly shrubs are unique in that some deciduous varieties are evergreen. They are also available as shrubs, climbing plants, and trees. While most people think of holly shrubs as having bright red berries, some produce black, yellow, white, or pink fruit. Holly plants are a great choice for many landscaping functions, such as providing a privacy screen or lining a foundation or walkway. They are eye-catching enough to work alone or to mix with summer-blooming plants to ensure your yard has visual interest in abundance, year-round.
Plan to plant your holly bushes either in the spring or fall. Cool temperatures and wet conditions allow the plants to settle into their new location with minimal stress. Holly does best when planted in a well-drained, sunny location. It prefers slightly acidic soil, although it tolerates a range of conditions.
Holly bushes are known for their bright red berries, and if this is the reason you are adding them to your landscape, you should plan the location carefully. Only the female bushes produce berries, so you'll want to plant the correct gender trees in a location that is prominent in your landscape and make sure male plants are nearby but in the background. An alternative is purchasing varieties that do not require males to produce berries.
Holly prefers full-sun locations, although many varieties will tolerate partial shade. When planted in a location with less access to sunlight, the foliage will be thinner than if it is planted in a sunny area. Aim for at least 4 hours of direct sun exposure to ensure your holly has dense foliage and a bountiful supply of berries.
When newly planted, the holly shrub requires daily watering. After the first week, you can reduce watering to twice a week. Once the holly is settled in and showing signs of new growth, you can reduce the watering sessions again, as long as the plant receives at least 2 inches of water each week.
Several pests can attack holly plants. If you notice white, fluffy masses on the underside of the leaves close to the ground, as well as a generally unhealthy appearance, your holly may have tea scale. Japanese wax scale causes white, waxy spots on the limbs and stems of the plant. The southern red mite causes small yellow or white spots on the leaves. When heavily infested, the leaves turn bronze. You can sometimes see the small mites on the underside of the leaves. The native holly leafminer creates elongated spots on the upper surface of the leaves. They tunnel through, so on close examination, you may see the leafminer maggots in the tunnels they create.
Phytophthora and black root rot attack when the holly is planted in an area that has poor drainage or remains wet. Other factors that may cause these conditions are over-mulching the holly, cool soil temperatures, and planting too deeply. The leaves will become yellow and eventually drop from the plant. Growth is stunted, and the stems will start to die back. Left untreated, the dieback will extend to the main trunk. Underground, the root system is suffering severe damage. Eventually, the plant will die.
Tar spot is a less severe disease that can affect holly. It is a fungal condition that develops in years with above-average rainfall. The leaves will turn yellow, progress to bronze, and finally turn black. The berries may be affected as well. Promptly removing and destroying parts of the shrub affected by the fungus and gentle pruning to encourage air circulation can help the holly fight this disease.
The ideal pH range for the holly is between 5.0 and 6.0. If necessary, you can raise the pH by applying dolomitic limestone or lower it with an application of elemental sulfur.
Fertilizing the holly early in the spring and again in the fall encourages growth and berry development. Any fertilizer marketed for azaleas or other acid-loving plants will work well for holly.
Pruning holly late in the winter encourages new growth and improves the shrub's shape. Be conservative when pruning, and never take away more than one-third of the overall size. Remove limbs that are old, leggy, or weak, as well as those that are growing outside the general profile you want to achieve. If you need to make additional cuts, remove the thickest stems, cutting back to ground level any that are thicker than your thumb.
You can propagate holly through hardwood cuttings. Take the cutting from the year's new growth while the plant is dormant. You want the cutting to be about 6 inches long, with all but the top two pairs of leaves removed. Deciduous holly plants will not have leaves at the time of year you take cuttings, and your cutting will be a bare stem.
Make your cut just below a bump on the stem. This bump is a bud union and is the spot where new growth is poised to develop during the next growing season. Dip the end of the cutting in rooting hormone and then place it in a spot in your garden that gets full sun and has loose, well-drained soil.
The holly provides wonderful winter color to your garden. You can enjoy its festive appearance in the home by decorating with cuttings during the winter months. The holly plant is also a valuable food source for many animals during the winter. Deer, squirrels, and many varieties of birds will visit your plants to feed on both the berries and leaves.
There are a variety of holly subspecies to choose from. Perhaps the most popular is the American holly. This is the traditional, festive-looking plant with shiny leaves and red berries. You can find self-pollinating varieties of American holly, as well as those that require both male and female plants to produce berries.
The Carolina holly is a popular choice in warmer climates. Hardy in zones 7 through 9, it does well in sandy soil. It is deciduous, losing its leaves when dormant. It does produce eye-catching red berries, but they fall from the plant easily and it is rare to enjoy them all winter long.
If you are looking for a drought-tolerant evergreen, the Chinese holly is a great choice. Some varieties can grow to 25 feet, and it tolerates pruning well, making it a popular choice for privacy hedges.