Planting & Fertilizing Chinese Holly
Chinese Holly (Ilex cornuta) shrubs vary in height but many cultivars grow from about 6 to 10 feet tall and are best used for hedges, screens and groundcover. Thick dark-green or green-yellow leaves are mostly oblong, stiff and somewhat spiny -- growing 1½ to 4 inches long. Bushes sprout small, off-white flowers and orange-red berries that attract birds and other wildlife. Popular Chinese Holly cultivars include: ‘Anicet Delcambre’ (also known as ‘Needlepoint’) with thin, glossy dark-green leaves; ‘Burfordii’ (20 - 25 feet high); ‘Carissa’ (3 - 4 feet high); ‘Dwarf Burford’ (5 - 8 feet high); ‘Berries Jubilee’ (6 - 10 feet high with large leaves and fruit clusters inside the canopy) and ‘Rotunda’ (3-4 feet high).
Habitat and Soil
Native to Asia but popular in America, Chinese Holly shrubs grow best in U.S. Department of Agriculture plant hardiness zones 7 to 9 (zero to 30 degrees Fahrenheit for low temperatures). Bushes thrive in deep, well-drained, sandy loam soil and in full sunlight or partial shade.
The soil’s pH balance may be neutral to slightly acidic; 6.0 to 7.0. Test the pH before planting; you can add 8 ounces of lime per bushel if the soil is too acidic. For deeply rooted hollies, mix in equal parts of peat moss and sand to help even the soil’s pH balance.
Composted leaves, bone meal, fish emulsion, cotton seed meal and seaweed produce organic fertilizers. Some, such as rock phosphate and limestone, do not come from living organisms but are just as effective. Using organic fertilizers in gardens is better for the environment and may decrease the amount of nutrient runoff into local water sources, notes University of Maryland’s Cooperative Extension. However, products are expensive and soil must be tested frequently.
Synthetic (chemical or inorganic) fertilizers are typically less expensive than organic brands because they are more readily available. Commercially-produced fertilizers contain the six macronutrients required for a healthy feeding; nitrogen, phosphorus, potassium, sulfur, magnesium and calcium. Other elements include zinc, chlorine, molybdenum, boron, manganese, copper and iron. Chemical fertilizers dissolve more quickly than organic feeders, allowing shrubs to absorb nutrients into their roots faster.
Fertilizing Chinese Holly
Fertilizers provide plants with three major macronutrients; nitrogen, phosphorus and potassium. Feed your Chinese Holly with a 10-10-10 (NPK) fertilizer once yearly, either in the early spring or late autumn – the amount needed depends on the size of the bush. For example, a three-foot holly may require 1½ pounds of fertilizers. Follow packaging instructions to ensure that you do not use too much chemical on the shrub because overfeeding can damage the plant’s roots. After fertilizing, protect the soil with mulch around the base of the shrub.
Leaf-yellowing, or chlorosis, may develop on Chinese Holly plants if soil pH is too high or the shrub is not absorbing enough nitrogen into its root system. To help summer’s yellowing foliage become green; apply a 10-5-5 fertilizer and water thoroughly. Foliage may also become a problem in dry, windy climates – especially if no other shrubs are planted near the holly bush. Young Chinese Holly cultivars and hybrids are susceptible to drying out.
Insects and Disease
Chinese Holly attracts “waxy” scale insects which look like large, white, sticky drops of wax. These bugs drop wax on the branches, about a ½ in diameter. Apply dissolved malathion to the shrub’s branches for pest control. Chinese hollies are not prone to many diseases although they can develop root rot and leafscald (scorch). Control root rot by sterilizing the soil and removing other diseased plants. Replant the holly in a partially-shaded area if it has scorched leaves.
Although nice to look at, holly berries are toxic to humans and pets -- do not eat them. Chinese holly is an evergreen but some Ilex cultivars are deciduous female and male plants. To produce berries in the pointed green foliage, plant one male shrub for every 5 to 10 females, advises University of Rhode Island Extension. Plants must be compatible and bloom simultaneously to exchange pollen.
© 2013 Teri Silver