The Freeman Maple
Sophie Nitoslawski
2020-10-05
It is fitting that Freeman maple (Acer x freemanii) should make it into the top 20 tree species profiled on this blog – it is an absolute favourite of many arborists and urban foresters in Canada. A hybrid of two well-known maples, silver maple (Acer saccharinum L.) and red maple (Acer rubrum L.), it is named after Oliver Freeman, who in 1933 was the first to cross the two species under controlled conditions for cultivation purposes. This hybrid has been known to occur naturally in regions where both maple species are native, such as the Great Lakes/St.Lawrence region and the southern Carolinian deciduous forests. In the Maritimes, this only occurs in the St. John River Valley region of New Brunswick on account of the distribution of silver maple.
Freeman maple is immediately recognizable in the fall season because of its brilliant red foliage, taking after one of its parents. One particular cultivar of this cross, ‘Autumn Blaze’, is widely planted along city streets for its fiery colour. Like silver maple, it grows relatively quickly to provide much-needed canopy, and like red maple, it is known for relatively strong branches and is hardy to a wide range of conditions one might find in urban landscapes. Freeman maple is often called upon to replace previous monoculture plantings of elm and ash, and is quite popular because of fast growth and showy canopy. It grows very upright with a dense canopy around its central stem, which makes it an ideal street and boulevard tree.
‘Autumn Blaze’ maple tree growing in an urban park. Source: https://www.plantingtree.com/products/autumn-blaze-maple
Freeman Maple Leaves. Source: https://www.boethingtreeland.com/plants/acer-x-freemanii-autumn-blaze/
If one is not fortunate enough to catch the autumn show, there are other ways one can identify a Freeman maple. Its leaves, occurring in an opposite pattern on the branch, comprise five relatively deep and sharply toothed lobes, often resembling those of the silver maple. If one is to turn over one of the bright green leaves, one will notice a silvery underside, another vestige of its parent. The bark of a young tree is smooth and light grey, becoming more fissured with age.
Examples of leaves taken from silver maple, red maple, and the hybrid Freeman maple. Source: https://landscapeplants.oregonstate.edu/plants/acer-freemanii
Unfortunately, Freeman maple is also known for its shallow root systems which, although less likely to infiltrate pipes and sewer systems, can be vulnerable to strong winds and storms. Hurricane Dorian, the powerful hurricane that struck the Bahamas in August 2019, also uprooted some trees in Halifax on its way back to the Atlantic – including a large but young Freeman maple on Vernon St. Nevertheless, one can appreciate how much that particular tree grew during its relatively short lifespan, as it was only planted as a small caliper tree 15 years earlier.
Storm damage on Vernon St., 2019. Photo Source: Peter N. Duinker
Yearly growth of the Vernon St. Freeman maple, as seen by its tree rings. Photo Source: Peter N. Duinker
Thriving in plant hardiness zones 3 through 7, Freeman maple will likely grow in Halifax and other Canadian cities for a long while. As our cities warm due to climate change and increased development, with more impervious surfaces contributing to the urban-heat-island effect, Freeman maple is poised to contribute significantly to the urban forest canopy due to its hardiness and ability to adapt to a wide range of site and climate conditions. We will be celebrating its lively and colourful presence for years to come!
Young Freeman maple along a path, North Common, Halifax. Photo Source: Peter N. Duinker