HARDINESS: Zones 4 to 9
PREFERRED SOIL pH: Slightly acid
PREFERRED SOIL TYPE: Average, well-drained
PREFERRED LIGHT: Sun to partial shade
ATTRIBUTES: Lustrous leaves, berries; for beds, specimens
SEASON OF INTEREST: Year-round for evergreens
FAVORITES: I. aquifolium, I. cornuta, I. crenata, I. glabra, I. x meserveae, I. verticillata
QUIRKS: Both male and female plants needed for good fruit set
GOOD NEIGHBORS: Boxwood, euonymus, juniper, spirea
WHERE IT GROWS BEST: Any soil and at least a hair day of sun
POTENTIAL PROBLEMS: Spider mites, scale
PRUNING: To shape plants, prune anytime from early spring to midsummer
CRITTER RESISTANCE: Good
SOURCE: Nursery plants
DIMENSIONS: 18 in-25 ft (45 7 cm-7.6 m) tall. 3-12 ft (1-3.7 m) wide
Holly in the Landscape
Fast-growing and easy to please, hollies are among the best shrubs to plant along the foundation of a house. And hollies with spiny leaves naturally deter traffic, making them excellent screening shrubs for boundaries. Modern cultivars are predictable in their sizes and shapes, so it is easy to choose hollies that fit into any spot and rarely need pruning. Although many do have prickly foliage, some species boast small, smooth leaves and are easy to include in a mixed border. The most popular hollies are evergreen, enriching the landscape with their glossy foliage year-round.
Hollies are also valued for their colorful berries in red, black, or yellow. However, for good fruit set, you will usually need at least one male plant for every six females. The sex of the plant is given on plant tags or often reflected in the cultivar name, such as 'Blue Boy' and 'Blue Girl'.
Sorting Through Hollies
There are hundreds of hollies, and while they are a vigorous, care-free group, it's best to select a variety suited to your region. English holly (Ilex aquifolium) does best in cool, moist climates, and its range is limited to Zones 6 and 7. Most have the classic wavy oval leaves with sharp spines and bright red or yellow berries, and plants usually grow to a height of 15 ft (4.6 m). A few cultivars, such as 'Silver Beauty' and 'Golden Milkmaid' have variegated leaves.
Meserve hollies (I. x meserveae) are very cold tolerant, being hardy from Zones 4 to 7. Also called blue hollies, these hybrids have glossy, spiny, blue-green foliage. Look for such cultivars as 'Blue Angel', 'Blue Prince', and 'Blue Girl", which all grow 6 ft (1.8 m) tall and 5 ft (1.5 m) wide. In hot, dry areas, look for the densely branched Chinese holly (I. cornuta), which grows from Zones 6 to 9. Many varieties grow to 10 ft (3 m), but 'Dwarf Burford' and 'Rotunda' are naturally rounded in shape and grow into tight mounds only 4—5 ft (1.2-1. S m) tall and wide. Lusterleaf holly (I. latifolia), hardy to Zone 7, is another good choice for hot climates. It has large, elegant, leathery leaves and grows to 25 ft (7.6 m) tall.
With small, smooth leaves that bring a fine texture to the landscape. Japanese holly (I. crenata) looks a lot like boxwood. Evergreen in Zones 5 to 8, this species needs moist soil and will not survive prolonged drought. The gracefully mounding 'Helleri', at only 18 in (45.7 cm) tall and 3 ft (1 m) wide, is a popular cultivar.
For damp, acid soil, look to two North American natives. Inkberry (I. glabra) is an evergreen with black fruits that grows 5-6 ft (1.5-1.8 m) and is hardy to Zone 5. Winterberry (I. verticillata) is deciduous, hardy to Zone 4, and grows up to 15 ft (4.6 m) tall and 10 ft (3 m) wide. 'Red Sprite' and 'Winter Red' have especially colorful and attractive berries.
Hollies can be planted in spring or early fall, or even in summer if you are willing to water them regularly. They should show vigorous growth the second season after planting and reach full size in 5-6 years.
Their tough, thick leaves are protection against most pests and diseases. Occasionally, minute sap-sucking spider mites or scale insects may attack, creating a pale stippled appearance on leaves. Knock mites off plants with a strong stream of water from a hose or apply insecticidal soap or a commercial miticide labeled for use on hollies according to label directions. Control scale with horticultural oil applied as directed.