ILEX OPACA – HOLLY, AMERICAN
The Pennsylvania Horticultural Society selected this plant as one of the Gold Medal Plants for 2001. This award recognizes exceptional woody plants hardy from New York to Washington, D.C. Growing well in full sun to partial shade, American Holly should be located on fertile, well-drained but moist, slightly acid soils below 6.5 pH. Berry production is highest in full sun and only on female trees if pollinated by a male plant. American Holly foliage thins during drought but insect and disease infestations are usually minimal. Foliage can burn in winter if exposed to direct wind. It tolerates salt air very well, growing along the secondary dunes in its natural habitat. Trees attract cedar waxwings, mockingbirds, robbins and many other birds.
Trees maintain a central leader and a conical shape even in the shade. The central leader form allows them to resist ice damage. Trees with double leaders will split in ice storms. American holly resists deer browsing which can be a problem on other hollys such as Nellie R. Stevens. Foliage can brown in strong winter winds. This plant is considered mostly allergy free and causes little or no allergy problems in most people. Trees are tolerant of urban conditions and have performed well as street trees. Plants serve as hosts for butterfly larvae.
Plants in the wild tolerate wet soil but those planted in yards appear to be intolerant of poorly drained soil. I (Dr. Gilman) think that if you plant trees when they are young they will be more successful in wet soils than if you plant a tree with a 2 inch trunk diameter or larger. Killing point for mature roots 9 degrees F.
This is the state tree of Delaware.
Wood is considered diffuse porous meaning that there is little difference in size of pores between spring and summer wood.
Transplant in spring or summer for best survival.