The Blue Princess Holly (Ilex meserveae ‘Blue Princess’) is a dense, broadleaf evergreen shrub prized for its dark, spiny foliage. This female cultivar is a popular choice for year-round landscape interest, especially during winter when its branches are often covered in bright red berries. Understanding its growth habits and ultimate size is important for prospective planters to ensure it fits the intended space.
Defining the Blue Princess Holly
This plant is a hybrid known as a Meserve Holly, created by crossing Ilex rugosa with the European Ilex aquifolium. The resulting shrub offers superior cold tolerance, making it suitable for a wide range of climates, thriving across USDA Hardiness Zones 5 through 9. Its distinctive blue-green foliage remains vibrant throughout the year, making it an excellent option for foundation plantings or evergreen hedges.
As a female plant, the ‘Blue Princess’ requires a nearby male pollinator, such as the ‘Blue Prince’ cultivar, to produce its characteristic red fruit. For reliable berry production, planting one male shrub for every three to five female shrubs is recommended. The shrub’s naturally dense, multi-stemmed structure easily fills out to the ground, providing excellent coverage.
Specific Growth Rate and Influencing Factors
The ‘Blue Princess’ Holly is generally classified as a slow-to-moderate grower. Once the shrub is established, the typical annual growth increment is expected to be between 6 and 12 inches per year. In optimal conditions, growth rates can reach up to 1 to 2 feet (12 to 24 inches) annually, classifying it as a moderate grower.
Several environmental factors directly influence this growth spectrum. Growth is maximized in locations that provide full sun exposure, although the plant will tolerate partial shade. A slightly acidic soil pH, ideally ranging from 5.0 to 7.0, along with consistent moisture and excellent drainage, promotes faster development. Conversely, planting in heavy shade or poorly draining, compacted soil slows the plant’s growth and overall vigor.
Managing the Shrub’s Mature Size
When left unpruned, the ‘Blue Princess’ Holly can reach a mature height of 10 to 15 feet and spread between 8 and 10 feet wide. The plant’s slow growth habit means it takes many years to reach these maximum dimensions. When planting multiple shrubs to form a dense screen or hedge, a spacing of 4 to 6 feet apart is recommended to allow the branches to intertwine.
For standalone specimens, spacing of 8 to 10 feet between plants ensures each shrub develops its full, natural form. Pruning is primarily done to maintain a desired shape, size, or density. Since the shrub flowers and produces berries on old wood, pruning should be performed in late winter or early spring before new growth begins to maximize the following season’s fruit set.
When reducing the plant’s size, selectively cutting back branches to a main stem or bud, known as renewal pruning, is preferable to shearing the tips. This method helps the shrub maintain a dense, natural appearance without sacrificing its winter berry display.