Mountain maple is the smallest of our native maple species. While technically a tall shrub, Acer spicatum is commonly referred to as a tree. This distinction is based on the size and stem of the plant. Shrubs are woody plants, generally under 20 feet (6.1m) and have many slender diverging stems extending from their base. Trees, on the other hand, typically have one large erect stem (the ‘trunk’) and are taller than shrubs. Therefore, their short size and lack of one distinct trunk classify mountain maple as a shrub, rather than a tree.
Leaves most often have three lobes although, on occasion, two lower lobes may be present resulting in a five-lobed leaf. Saw-toothed edges are present on all leaves. Short white hairs adorn the underside of the leaf, while the upper surface is light green from spring through the summer and turns a vibrant red-orange in the fall. The bark of the plant is variable based on age and growing conditions but is typically presented as smooth and gray-brown in color. In June, the shrub produces tiny white flowers on long erect stems. The flowers produce the notable two-winged fruit typical of all maple plants. The fruit is smaller than other maples and turns a bright red overtime. Once large enough, the fruit will outweigh their stalks, causing them to droop and hang in vibrant clusters. Other names for the tree include dwarf maple (for its short size) or moose maple (for its attractiveness as a food source for moose in other provinces).
Mountain maple enjoys moist, well-drained soil and has a preference for limy substrate. They thrive along stream banks and other riparian areas. In comparison to other maples, mountain maple has the most northerly range and can tolerate a cold climate. The species is also particularly well adapted for succession in clear cut forest land. However, despite their aptitude for cleared land, the plants are also shade tolerate and do well as understory vegetation
For this species, seed dispersal is not the primary means of reproduction. Rather, vegetative propagation is much more widespread. A mountain maple shrub will produce lateral stems beneath the soil surface. These stems will infiltrate surrounding areas and in time break the surface as “new” shrubs. Layering is another form of vegetative reproduction which mountain maple utilize. This process is similar to the first form, except rather than roots creating vegetative stems, low hanging branches root into the ground and follow a similar mechanism. Despite their affinity for vegetative reproduction, it is possible to grow them yourself from seed. At the Macphail Woods nursery, we collect seeds in the fall once they start to dry. Then we plant the seeds so that they are almost touching, in rows 4” (10cm) apart in a nursery bed. Cover the seeds with about ¼” (.64cm) of soil, and mulch for the winter. In the spring, the mulch is removed to allow the soil to warm. After germination, keep the seedlings watered and weeded. Transplant to give them more space as needed, once the true leaves have appeared.
Mountain maple is an excellent soil stabilizer and is a significant plant in riparian areas. Off-island, mountain maple buds provide ample forage for deer and moose. Beaver, snowshoe hare, and ruffed grouse all browse heavily on mountain maple buds on Prince Edward Island. Ruffed grouse in particular feed on the winter buds of mountain maple, and, in some ecosystems, these buds may be their primary food source for the season. Mountain maple is uniquely adapted to manage susceptibility to heavy browsing, to the point where shrubs are more productive when they are browsed thoroughly and frequently. In fact, an 80% removal of new branch growth each year results in peak productivity. Their vigorous growth after forage makes them an ideal and ample food source for a wide variety of herbivores.
Areas of Usage:
Their primary use in today’s society is, as previously mentioned, as a bank stabilizer to prevent soil erosion in riparian areas. However, the history of their usage by Indigenous peoples is ample. Primarily, the plant was used to treat eye irritation. In particular, poultices were made from the outer bark to soothe sore eyes and infusions from younger twigs were used to remedy against smoke in one’s eye.
A big thank you to Jenna Marie Cahill for contributing this nature guide.