Carissa holly is a compact, dense evergreen shrub with small, glossy, dark green leaves, each with a single terminal spine (Figure 1). The somewhat-showy clusters of fragrant, springtime, white flowers are followed in fall and winter by bright red berries. However, the berry display is mostly inferior to Ilex cornuta 'Burfordii'. The shrub stays small, eventually growing to about 8 feet. Most carissa holly plants are kept smaller than this. The plant occasionally reverts back to a 'Rotunda' holly leaf form, a plant to which it is closely related. 'Rotunda' has many spines along the margins of the leaf.
Scientific name: Ilex cornuta 'Carissa'
Pronunciation: EYE-lecks kor-NOO-tuh
Common name(s): carissa holly
Plant type: shrub
USDA hardiness zones: 8 through 10 (Figure 2)
Planting month for zone 8: year round
Planting month for zone 9: year round
Planting month for zone 10 and 11: year round
Origin: not native to North America
Uses: border; mass planting; cut foliage/twigs; superior hedge
Availablity: generally available in many areas within its hardiness range
Height: 3 to 4 feet
Spread: 4 to 6 feet
Plant habit: round
Plant density: dense
Growth rate: slow
Leaf arrangement: alternate
Leaf type: simple
Leaf margin: terminal spine
Leaf shape: ovate
Leaf venation: pinnate
Leaf type and persistence: evergreen
Leaf blade length: 2 to 4 inches
Leaf color: green
Fall color: no fall color change
Fall characteristic: not showy
Flower color: white
Flower characteristic: spring flowering
Fruit shape: round
Fruit length: less than .5 inch
Fruit cover: fleshy
Fruit color: red
Fruit characteristic: rarely fruits
Trunk and Branches
Trunk/bark/branches: typically multi-trunked or clumping
stems; not particularly showy
Current year stem/twig color: green
Current year stem/twig thickness: medium
Light requirement: plant grows in part shade/part sun
Soil tolerances: slightly alkaline; clay; sand; acidic; loam
Drought tolerance: high
Soil salt tolerances: poor
Plant spacing: 36 to 60 inches
Roots: usually not a problem
Winter interest: no special winter interest
Outstanding plant: not particularly outstanding
Invasive potential: not known to be invasive
Pest resistance: long-term health usually not affected by pests
Use and Management
A dense, rounded silhouette develops without clipping making it well suited for planting along a foundation. Plant 3 to 4 feet apart to form a hedge, farther apart in a shrub border. It is often used as a mass planting on commercial properties to form a tall ground cover or low shrub mass around parking lots. One yearly pruning can easily keep this plant in bounds in most landscape settings, unless it is clipped into a formal hedge. Two or three clippings may be needed for hedges. It shears fairly well, but will thin slightly toward the base, especially if not located in full sun. Clip the hedge so it is wider at the bottom than at the top to allow maximum light penetration to bottom foliage. This will help keep the hedge full to the ground.
Growing best in rich, well-drained, slightly acid soil, carissa holly does well in full sun or part shade. The plant is very drought tolerant, requiring little, if any, irrigation once established in the landscape. One or two fertilizations are all that is needed to maintain good leaf color and adequate growth.
Propagation is by cuttings only.
Pests and Diseases
Holly can be bothered by scale insects and aphids.
No diseases are of major concern.