In certain enthusiast circles, there is a lot of passion around the question of “natives.” This article puts together some background and thoughts for you to explore and further research on your own.
First, in the conversations around “doing gardens better,” you will hear a number of terms which are related but distinct from one another, even though sometimes they are lumped together almost as though they were synonyms. These will be explained as we go in the discussion. Some of these terms include pollinators, natives, naturalized, invasive and growing zones.
Native Advocacy on the Spectrum
Natives generally refer to plants which have evolved in place for a VERY long time. It’s important to note that when people use this term as shorthand, they do not necessarily mean the same thing, because advocacy for natives exists on a spectrum.
At the purist pole, natives not only mean regionally or locally indigenous – or in fancy terms, autochthonous – but also right context. So, for example, for a Detroit garden, a plant should be native to the Detroit area and used in its native context: a woodland plant should be used only in a woodland setting, or a waterway plant should only be used along a waterway.
Adding a dash more flexibility, natives are used in a setting which is compatible with the attributes of the plant. For example, a woodland plant is going to do well in shade or partial shade, even if your shade is due to a 6’ corridor in between your 2-story house and the neighbors’. Right region, some overlapping conditions, wrong context. Or, more benevolently, a curated context.
Next, we scale rigid adherence in terms of location. Is it native to Detroit, SE Michigan, Michigan, Eastern US, the Midwest, the US? You will see argument and liberal curated use for any of these origin stories, so long as we’re still splitting definitions over continents. The most flexible pole within the native discussion is embracing any plant from the continent which is appropriate for your growing zone.
The growing or hardiness zone is based on temperature and, to lesser degrees, water/soil/climate. As examples, you cannot grow California White Sage outdoors in Michigan, because the winter will kill it. Northern Highbush Blueberry will not thrive in Florida, because the heat will kill it. A plant from a dry climate with similar temperatures will often rot in humid locations. Detroit is usually considered to be Zone 6a, with microclimates (pockets) of 6b (slightly warmer). Therefore, a very flexible nativist approach would consider American Persimmon, which does well in Zone 6, compatible and appropriate – but it originates in the mid-Atlantic. Domestic, but not local.
Enter Naturalization
Pangea is a real thing and just like with human migration, plants have found themselves on continents and in places where they didn’t start or may strike us as unexpected. Sometimes, that happened thousands of years ago. Sometimes, it happened in the last century – or maybe even yesterday. Southern Beech, for example, is found natively in South America and Australasia, due to continental drift. Broadleaf Plantain is not native to North America, but it has been here long enough that Native Americans regard it as heritage medicine.
There are some who believe that anything non-native is not as “good” as a native plant, or even inherently destructive. This is in the camp of advocates like Douglas Tallamy. The argument here is that because the plant did not co-evolve with the surrounding ecosystem, it does not support the same diversity of birds, insects, etc.
The feedback loop in nature is rarely that simple and ecology does not support that position as an absolute. While it seems obviously true that the migration of some plants resulted in responsive ecosystem changes, that is not inherently destructive and may be positive in some cases. Conceptually, an extrapolation of hybrid vigor is an idea which could be applied. Immigrant plants which survive in a new landscape may offer redundancy, a cornerstone of resilience in a system; may fill a gap or niche; and may offer other value to the soil, watershed or creatures in place. Peter del Tredici is an advocate for a more utilitarian view of the question.
Scientifically, plants occupy categorical niches which, while not congruent, can be viewed as interchangeable along some metrics. As a nitrogen fixer, for example, or deer forage. Therefore, naturalized plants can both overlap and expand the capacity of an ecosystem. Some present all non-natives as essentially a “dead zone” for local birds and insects; this is not supported in ecology.
Curated naturalized plants are an important topic to consider in permaculture, because so many are involved and desirable in herbalism. In fact, that is often why they were brought across eco and state borders – as a kind of familiar, portable and perpetual medicine kit. There are also many naturalized food plants which are used in curated guilds, or intentional plant grouping.
Invasives
While there is debate about the value of naturalization, few would argue that the whole point of the label “invasive” is because it is harmful. Invasives designate plants, by definition, which are not native and which essentially out-compete plants which are. Existentially, we can appreciate their drive to survive, and their ability to do so, but in terms of managing our landscape, we tend to be more war-like in our view. The biggest risk is that they can transform the landscape into a monoculture, or a place with just one dominant plant, which weakens the whole system.
Even with the label “invasive,” there are ideas to consider. We don’t call natives invasive, no, but certainly they can act the same. The use of othering and colonial language aside, plants like Goldenrod, Hedge Bindweed and Virginia Creeper – all native – will take over a yard faster than Kudzu on Magnolia. Therefore, managing aggressive and/or invasive plants, no matter their origin, should always be a first focus.
With that being said, whom you are and what you’re doing matters. For example, Japanese knotweed is highly invasive in Michigan. It is literally prohibited. Yet, it is everywhere. And, it is one of the most powerful plant medicinals which has no native equivalent. Don’t plant it: it’s illegal. If you happen to have it, cull it as best you can. And, use everything you cull: eat the peeled stalks or young leaves, dry the roots for tinctures and teas, make a leaf poultice. Goldenrod, a native which will take up some space if you let it, extends the season for pollinators, can create a yellow dye, can be eaten, and has many medicinal uses. The point is that we are not in a reflexive war with our landscape; instead, working on a deeper understanding of the system in front of us helps us to make the right choices for the right reasons.
The Permaculture Lens
Throughout this discussion, the word permaculture has been thrown in without much explanation. It is an entire field of study, itself. But briefly, why I mention it here is because it is both an ecological philosophy and a methodology which informs choices around what, where and why. Permaculture does prioritize natives, but it does not exclude other options. Instead, permaculture seeks to understand ecological systems – how things work together and why, their relationships – through observation and experimentation. This includes people, plants, animals, insects, birds, soil, water, light and sometimes even less obvious influences, like the moon. Because the system is being studied holistically, not mechanistically, it can be expansive. And it takes a utilitarian view that all gardens are curated, and people want or need foods, medicine or beauty which may have diverse origins, thus, it focuses on how to best achieve an “ecological eclecticism” which is respectful, resilient and robust.