This small-statured native shrub with attractive, glossy foliage and dark berries flourishes as an understory planting in moist woodlands. The leaves, which are similar to those of the alder tree, turn an attractive shade of yellow in fall, and the black berries are a food source for birds. An additional bonus is a lack of thorns. The plant is native to the upper half of US and southern half of Canada.
Its primary means of reproduction is “layering:" the horizontal stems and branches produce roots and spread to create large colonies. This method of spreading is effective at reducing soil erosion and runoff into waterways, and alder-leaved buckthorn is often found in or near water features. This native can be distinguished from the invasive, non-native buckthorns by its short stature, obvious stipules at the base of the leaf stalk, 5-parted flowers, and leaves with rounded teeth and 5 to 8 veins per side. Glossy buckthorn (Frangula alnus) has toothless leaves with 6 to 9 veins per side, and common buckthorn (Rhamnus cathartica) has 4-parted flowers and leaves with rounded teeth and only 3 or 4 veins per side. The non-natives grow significantly taller and bushier than the native, and they produce many more flowers and fruits.
Native habitats include moist and shady bogs, fens, moist woodlands, and edges of lakes.
Plant Characteristics:
Grows 2-3' tall.
Prefers part sun.
Prefers moist to wet soils.
Yellowish-green flowers bloom May-June and are small, ¼ inch or less across, 5 pointed and short stalked, in clusters of 1 to 3 in the leaf axils of new growth. The triangular sepals surround a flattened, saucer-like receptacle. Male and female flowers are on separate plants. Fruit is a short-stalked, shiny, black berry up to 1/3 inch in diameter, with 1 to 3 seeds inside. The berry is often irregularly slightly lobed with a faint groove on the surface between each seed.
Oval or oblong lance-shaped leaves are simple and alternate, 2 to 4½" long. Margins have rounded serrations.
Wildlife Value:
Flowers attract pollinators and birds eat the berries.
Medicinal, Edible, and Other Uses:
Native Americans used the plant as a laxative.
Caution: Berries may be toxic.
Resources:
Minnesota Wildflowers: https://www.minnesotawildflowers.info/shrub/alder-leaved-buckthorn
Wikipedia: https://en.wikipedia.org/wiki/Rhamnus_alnifolia
Ontario Trees and Shrubs: https://ontariotrees.com/main/species.php?id=2021