Thankfully something in our soil killed off their seedlings and without the modern convenience of compost and fertilizers there wasn’t much the settlers could do. This left the native black walnut (Juglans nigra) to dominate the useful-in-every-way category in early North America. Think I’m exaggerating?
The black walnut produces an edible nut (it’s a lot of work to get to them, but rumour has it they’re delicious), which makes the species work great as part of an agroforestry system (grow corn and walnuts!). Its nut husks and outer bark can be used to make a dark brown dye and the leaves can be used as pet bedding to repel fleas.
The bark at one time was medicinally used by First Nations to treat a long list of ailments, while the wood was found to be strong, beautiful, and rot-resistant. In the past these trees were cut extensively for furniture, greatly decreasing the number of good timber producing populations. For a while, lighter coloured woods increased in popularity (thanks IKEA), which gave the walnut some time to recover. But it didn’t take long for the trend to start reversing.
To top it all off, the tree itself is gorgeous. Black walnuts can grow up to 30m with a nice, open, rounded canopy and grey furrowed bark. The leaves are compound (meaning many “leaflets” that are attached to a main leaf stem) with up to 22 leaflets per leaf. In the fall they are often one of the first tree species to show leaf colour change, but don’t worry; the early leaf loss is not a sign of problems (at least not with this species)! The leaves turn an almost a fluorescent golden-yellow when they change colour in the autumn, causing this tree to stand out in the crowd.
Unfortunately, these guys face a certain degree of prejudice. Young saplings are often mistakenly identified as tree of heaven (trust me, it’s anything but) or staghorn sumac (not a chance) leading to them being yanked out before they have a chance to establish.
The black walnut is considered undesirable in many urban areas because of the juglone chemical (produced through its nut, roots and decomposing leaves) that represses growth in other plants – but if you want to stop weeding, this may be the tree for you!
Love the idea of the black walnut, but worried that you may not being able to grow a beautiful garden anywhere near it? Don’t be! There are many tree, shrub, perennial, and vine species that are resistant to juglone and can grow quite happily under these glorious trees.
LEAF offers black walnut as part of our Backyard Tree Planting Program, so if you’re interested in taking a chance on a beautiful yet misunderstood tree, book a consultation with one of our arborists today!
Join me next month when I explore the life history of the mighty and magnificent bur oak.