Ilex is a plant genus comprising over 400 species of shrubs and trees that are native to several regions including the Americas, Europe, Asia, and Africa. One species that is particularly popular among gardeners and landscapers is Ilex crenata. This evergreen shrub is commonly known as the Japanese Holly. It grows 6 to 10 feet in height and spreads a similar width. Its dense foliage, consisting of dark green leaves, covers the small, black, berry-like fruits from view. It naturally develops into symmetrical clumps, which makes it a ideal shrub for hedges, formal gardens, or foundation plantings.
There are several things to consider when planting and growing the Japanese holly. The condition of the soil, the climate, and certain pests or diseases can affect the health of Ilex crenata.
Climate
This shrub does well in hardiness zones 6 to 8. It prefers partial shade, but can tolerate direct sunlight.
Soil Requirements
It is best to plant the Japanese holly in soil that has a slightly acidic pH. The soil should also be porous, allowing for good drainage. If the soil is too compact, water will become stagnant, which could damage the roots.
Watering and Fertilizers
As long as the soil is well-draining, maintain a regular watering schedule. Although it is recommended to keep the soil moist, this species is drought tolerant and can survive without water for a time. This shrub naturally grows well, so additional fertilizers isn’t required.
Propagation
To propagate the Japanese holly, it is recommended to take cuttings and plant them in ideal soil conditions.
Pests and Diseases
Spider mites are tiny insects that suck the sap from the leaves of this shrub. Another problem that affects this shrub is Thielaviopsis blight, which is a fungal infection that damages the roots. Usually, fungicidal spraying or drenching is required to stop the spread of this fungus.
Reference:
Ilex crenata (Japanese holly) – Fine Gardening.
Erv Evans. Shrubs: Ilex crenata – North Carolina Cooperative Extension
April Sanders. Pests and Diseases of Japanese Holly – Garden Guides