At a glance:
- Soil needs: Not picky about soil type, tolerates even very poor soils.
- Water needs: Moderate. Likes moist soils, and can tolerate periodic flooding. Also drought tolerant, once established.
- Sun needs: Full sun to part shade. Less shade-tolerant than most maples.
- Size needs: Small to medium. At full size, up to 35-80 feet tall, with a spread of 35-50 feet. Great for mid-canopy coverage.
- Growth rate: Fast. Also sends out suckers. Considered a weed by some, so make sure you want it!
- Tolerates Black Walnut: Yes, this tree can be planted near Black Walnut.
- Wildlife value: High. Special value to bees (like most other maples). In addition to supporting all the same bugs and birds as all the other maples, it is especially favored by boxelder bugs and evening grosbeak birds.
A bit more…
Boxelder maple, or Acer negundo, is one of the twelve maple species native to North America. It is also known as box elder, Manitoba maple, or ash-leaved maple. It is a maple through and through, yet to me feels very different than most. I tend to think of maple trees as single trunk, high canopy, non-suckering trees. Basically, your stereotypical “tree.” Boxelder is none of those. It sends out suckers so can have multiple major trunks. And while it can get pretty tall, it often retains its branches and foliage all the way down. This makes them quite useful as sub-canopy and understory trees, unlike most other maples. This fact, combined with the suckers, can mean they sometimes form thickets, which has led to some people considering them “weedy.” While this can increase their ecological value in many situations, it is nevertheless an important trait to consider before choosing one for your property.
Another aspect which sets them apart from other maples is their leaves. The typical pointy/lobed maple leaf is an iconic symbol of the genus, especially since we’ve spent our whole lives seeing it on flags, etc. But the boxelder maple is different, having compound leaves. In fact, it is one of the only plants which can fool me into thinking it is poison ivy. It can come in sets of three, with one or two large notches, and even some red at the intersection (see photo below). Of course, if you inspect a bit more thoroughly, the misconception quickly vanishes. The leaves can also come in sets of five or seven, some are much more deeply lobed, and some look like mittens.
The other main iconic feature of the Acer genus is the samara, or the helicopter-like winged seed. In that aspect, the boxelder maple is no different — it too has the iconic winged seeds. But even though the seeds are similar, the boxelder is different from other maples in that it is fully dioecious, meaning each tree only has either male or female flowers. Thus, there must be both male and female trees nearby in order to fertilize seeds.
The boxelder maple has many other features in common with most maples, of course. One is that they can be tapped for syrup. But perhaps a more important one is that they are one of first blooming trees of the season. Just as the maple trees help pull us out of our winter gloom with their early flowers, pollinators rely on these early blooms as well. Especially bees. If the bees start to emerge from winter slumber and do not find nectar to sustain them, they may not survive. Thus, a having enough maple trees in the landscape is crucial. They are also host to at least 285 species of butterflies and moths, which are the main source of food for birds trying to rear their young. One stunning example is the cecropia silk moth (Hyalophora cecropia), which favors maples. It is of course worth noting that boxelder maples are also well known for being the favored host of the boxelder bug (Boisea trivittata). This bug can swarm into large numbers, which can be off-putting to some people. They can also wander into homes if the boxelder tree is close by, although they are harmless. If you absolutely cannot stand boxelder bugs, then perhaps the boxelder maple is not for you. But these bugs do provide additional environmental benefit. While they are not a first-choice food source for many animals, birds will indeed eat them if other food sources are running short. Speaking of food running short, boxelder maple has yet another perk there — some of its seeds remain attached through the winter and into spring, so it is a valuable source of food for birds and mammals throughout the winter.
One last thing worth mentioning about boxelder maples is that they tolerate a very wide range of soils, including very poor and very dry. This makes them a key pioneer species, and very useful if you are just starting your journey of re-wilding an area that may be very disturbed or derelict.
