Ilex cassine: Dahoon Holly

Edward F. Gilman, Dennis G. Watson, Ryan W. Klein, Andrew K. Koeser, Deborah R. Hilbert, and Drew C. McLean


Introduction

Attractive when tightly clipped into a tall screen or allowed to grow naturally into its single-trunked, small tree form, dahoon holly is ideal for a variety of landscape settings. Capable of reaching 40 feet in height, dahoon holly is usually seen at a height of 20 to 30 feet with an 8 to 12-foot spread. The smooth, supple, shiny dark green, evergreen leaves, two to three inches long, have just a few serrations near the tip. Possessing male and female flowers on separate plants, at least two dahoon hollies (male and female) must be planted in the landscape to ensure production of the brilliant red berries in fall and winter. The berries serve as an excellent food source for wildlife but are far less prevalent than on East palatka or Fosters holly.

Figure 1. Full Form—Ilex cassine: Dahoon holly
Figure 1.  Full Form—Ilex cassine: Dahoon holly
Credit: Ed Gilman

General Information

Scientific name: Ilex cassine

Pronunciation: EYE-lecks kuh-SIGH-nee

Common name(s): Dahoon holly

Family: Aquifoliaceae

USDA hardiness zones: 7A through 11 (Figure 2)

Origin: native to the southeastern United States

UF/IFAS Invasive Assessment Status: native

Uses: hedge; screen; specimen; street without sidewalk; deck or patio; reclamation; sidewalk cutout (tree pit); tree lawn 3–4 feet wide; tree lawn 4–6 feet wide; tree lawn > 6 ft wide; urban tolerant; Bonsai; highway median; container or planter

Figure 2. Range
Figure 2.  Range

Description

Height: 20 to 30 feet

Spread: 8 to 12 feet

Crown uniformity: irregular

Crown shape: pyramidal, oval

Crown density: open

Growth rate: moderate

Texture: medium

Foliage

Leaf arrangement: alternate

Leaf type: simple

Leaf margin: entire, serrate

Leaf shape: elliptic (oval), oblong

Leaf venation: pinnate

Leaf type and persistence: evergreen

Leaf blade length: 2 to 4 inches

Leaf color: dark green and shiny on top, paler green underneath

Fall color: no color change

Fall characteristic: not showy

Figure 3. Leaf—Ilex cassine: Dahoon holly
Figure 3.  Leaf—Ilex cassine: Dahoon holly

Flower

Flower color: male—greenish white; female—white

Flower characteristics: not showy; male—emerges in branched clusters; female—emerges solitary or in clusters

Flowering: late spring to early summer

Figure 4. Flower—Ilex cassine: Dahoon holly
Figure 4.  Flower—Ilex cassine: Dahoon holly

Fruit

Fruit shape: round

Fruit length: 1/4 inch

Fruit covering: fleshy drupes

Fruit color: yellow, orange, or red

Fruit characteristics: attracts squirrels/mammals; showy; fruit/leaves not a litter problem

Figure 5. Fruit—Ilex cassine: Dahoon holly
Figure 5.  Fruit—Ilex cassine: Dahoon holly

Trunk and Branches

Trunk/branches: branches droop; not showy; typically multi-trunked; no thorns

Bark: dark gray, thin, and smooth, becoming scaly with age

Pruning requirement: little required

Breakage: resistant

Current year twig color: green

Current year twig thickness: medium

Wood specific gravity: unknown

Figure 6. Bark—Ilex cassine: Dahoon holly
Figure 6.  Bark—Ilex cassine: Dahoon holly
Credit: Gitta Hasing

Culture

Light requirement: full sun to partial shade

Soil tolerances: clay; sand; loam; slightly alkaline; acidic; wet to well-drained

Drought tolerance: moderate

Aerosol salt tolerance: moderate

Other

Roots: not a problem

Winter interest: no

Outstanding tree: no

Ozone sensitivity: unknown

Verticillium wilt susceptibility: resistant

Pest resistance: resistant to pests/diseases

Use and Management

Growing well in full sun to partial shade, dahoon holly does best on moist soils since the wet, boggy soils of swamps is its native environment. Dahoon holly can tolerate drier locations with some watering, but often has a thin crown in this environment. It is not recommended in the southern part of its range in a dry, exposed site unless irrigation is provided. It lends itself well to use as a specimen or street tree, and is ideal for naturalizing in moist locations. Little pruning is needed to create a well-structured, strong tree. It appears to adapt well to the confined spaces of urban and downtown landscapes and is tolerant of some salt spray. The crown is fuller in full sun.

Ilex cassine var. angustifolia, Alabama dahoon, has narrower, more linear leaves than the species and more abundant but smaller berries. Ilex myrtifolia has smaller leaves and fruit, and its cultivar `Lowei' has yellow berries and dark green foliage.

Propagation is by seeds, which germinate in one year, or by cuttings. Cuttings are preferred since they give plants of a known sex and also root easily.

Pests and Diseases

No pests or diseases are of major concern. A twig gall sometimes forms in response to a fungus infection. Mites can infest foliage on trees planted on dry sites.

References

Koeser, A. K., Hasing, G., Friedman, M. H., and Irving, R. B. 2015. Trees: North & Central Florida. Gainesville: University of Florida Institute of Food and Agricultural Sciences.

Koeser, A.K., Friedman, M.H., Hasing, G., Finley, H., Schelb, J. 2017. Trees: South Florida and the Keys. Gainesville: University of Florida Institute of Food and Agricultural Sciences.

Footnotes

1. This document is ENH458, one of a series of the Environmental Horticulture Department, UF/IFAS Extension. Original publication date November 1993. Revised December 2006 and December 2018. Visit the EDIS website at https://edis.ifas.ufl.edu for the currently supported version of this publication.
2. Edward F. Gilman, professor emeritus, Environmental Horticulture Department; Dennis G. Watson, former associate professor, Agricultural Engineering Department; Ryan W. Klein, graduate assistant, Environmental Horticulture Department; Andrew K. Koeser, assistant professor, Environmental Horticulture Department, UF/IFAS Gulf Coast Research and Education Center; Deborah R. Hilbert, graduate assistant, Environmental Horticulture Department, GCREC; and Drew C. McLean, biological scientist, Environmental Horticulture Department, GCREC; UF/IFAS Extension, Gainesville, FL 32611.