MJ’s Eco Corner: What’s in Bloom?: American Holly (Ilex Opaca)

Holly-DOP.jpgOnce all of the leaves have fallen in late fall American holly (ilex opaca) trees start to sparkle in the winter sunlight. Unobtrusive throughout the summer their broad, prickly, waxy evergreen leaves, and bright scarlet berries stand out, bringing color and life into the park during the cold winter days.

American hollies can tolerate a variety of soils, from moist swampy soil to very dry sandy soils; growing where they can get full or partial sun. They are among the few forest trees, along with hemlocks, cedars, and magnolias, which remain bright green and covered in leaves year round. They produce small, yellow green flowers which appear in late spring to early summer and are an important source of nectar for bees and other insects- a perfect example of a symbiotic relationship as cross-pollination is necessary for berry production.

holly-dop2The American holly is  favored by small songbirds as a rich source of food and small mammals for their berries and the shelter they provide. Their dense, prickly leaves offer protection in foul weather and are ideal nesting sites.

Pruning of American hollies is often done in early December. so that the cut branches can be used during the holidays. Their bright red berries make them favorite for wreaths and swags. Beatrix Farrand herself, was aware of this trend, and offered advice to conservation-minded buyers to only purchase wreaths from nurseries that sourced the garlands from potted trees grown on-site in order to prevent the cutting of woodland branches.

American hollies are the ideal tree to grow in a native woodland garden like Dumbarton Oaks Park. In addition to offering food and shelter for wildlife, it provides hue and structure in the Park during the bare winter months. Our biggest grove of American hollies is located near the northwest entrance of the park below the Danish Embassy, many of these trees are newly planted, but with enough room to grow, partial sunlight, and moist soil, they will eventually become beautiful large specimen trees.