By Geneva Langley, Wild Gardens of Acadia Supervisory Gardener
Late summer in the Wild Gardens brings with it the expected transition from flower to fruit. Of course, there are many plants still coming into bloom, such as cardinal flower, boneset, summersweet and goldenrod, and some whose season has not yet arrived, such as ground nut, water willow and many of the asters. However, we have clearly passed the midpoint of the season and many specimens are heavy with fruit.
Our native hollies (family Aquifoliaceae) are one group of plants whose fruit draw more attention than their blooms. Hollies are dioecious, which means there are separate male (staminate) and female (pistillate) plants. The flowers are small and greenish-white, hardly noticeable if it weren’t for the many bees and other insects attracted to the nectar. When the flowers of May and June pass, small green berries develop along the stems of the shrubs and begin to ripen come August.
One of our native hollies, the mountain holly (Ilex mucronata), is found not only on mountains, but also in bogs, wooded swamps and other cool, moist and acidic environments. Mountain holly shrubs have oval, toothless leaves with a distinctive purple leaf stalk (petiole). In late summer, the shrubs are laden with satiny fruits in a deep, rich, saturated crimson. The intense red berries persist for a few weeks before cedar waxwings and robins descend upon the shrubs and consume every single fruit over the course of a few days.
The fruits of another deciduous native holly, the winterberry (Ilex verticillata), are just now showing the first flush of color. Winterberry is most often found growing on wetland edges in moist, acidic soil. The bright scarlet berries heavily clustered along bare gray twigs are an iconic part of the early winter landscape here on Mount Desert Island. The fruits are eaten by overwintering birds, but not until very late in the season. There is some speculation that the berries do not fully ripen until then or may need freezing temperatures to become palatable.
The last holly native to Acadia National Park has not yet found its way into the Wild Gardens. It is the inkberry (Ilex glabra), an evergreen species that is more commonly found from Massachusetts south. In Maine, inkberry is listed as an endangered species by the Maine Natural Areas Program, and is known only from Isle au Haut. The glossy, leathery leaves of inkberry provide cover for birds and mammals and its black fruits provide food. However, it is important to note that all holly berries are unsafe for humans and pets to eat. They contain theobromine, a chemical similar to caffeine, but in toxic quantities.
What is in bloom at the Wild Gardens: rattlesnake plantain (Goodyera pubescens), germander (Teucrium canadense), cardinal flower (Lobelia cardinalis), boneset (Eupatorium perfoliatum), jewelweed (Impatiens capensis) and summersweet (Clethra alnifolia)