Planting Native Plants For The Wrong Reasons

As part of a well intended effort to convince more gardeners to incorporate native plants into their gardens (or even to rip out all non-native plants and replace them with native), a very unhelpful marketing trend has taken place.  Instead of focusing on the individual virtues of specific native plants, there has been a somewhat lazy blanket philosophy pushed that native plants in general are easier to grow because they are already adapted to the local conditions and will need no care after planting...  This makes me cringe.

Let's back up and look at some broader points to create perspective.

Why do some invasive plant species invade and displace native species if native species are better adapted than non-native?
The simple truth is that plants from all over the world have adapted to all manner of growing conditions and when they are moved around, they sometimes end up in locations which allow them to grow just as well, and sometimes even better than they were able to in their original native habitats.  Sometimes this is just a matter of chance in that a plant has evolved a trait which is mildly beneficial or even neutral, but not harmful in its home range, but that same trait just so happens to be especially beneficial to it in a location where it is introduced.  Additionally, native plants have native pests and diseases.  That's all part of balanced ecosystems.  Sometimes, when a plant is introduced to a new area, some or all of its native pests and diseases do not make the journey with them.  This allows them to grow with less constraints than they had back home.  Meanwhile, our locally native species are growing right where they evolved along with all the environmental pressures that keep them in check!  

Why do we not see every native species from an area thriving in every location within that region?

It's tempting to look at a native plant growing wild and observe how well it is growing, only to assume it's doing so well purely because it's native.  However, what we're not seeing is that for every specimen you see doing well, there were countless seedlings of that same species which died off soon after germinating because they didn't end up in a spot that was hospitable for them even though it was their native range.  Within any given region, there are still many variables in things like sun/shade exposure, seasonal differences in water availability, soil type, depth and variations in nutrient availability, site specific pressures from native fauna which utilize them and even just competition from other native plant species.  Afterall, it is not just non-native plants which displace native plants.  Even native plants displace other native plants just by occupying the space they are in.  

For these reasons, it is quite important to put the same amount of thought into your planting choices regardless of whether you are planting something native or not.  Do your best to evaluate which places on your property are likely to best support which specific species, and forgive yourself if you don't get it right every time.  Some trial and error will always be necessary regardless of how much effort you put into preparation.  Consider if the plant you are intending to add to a spot will "play well" with the other plants you wish to grow there or if it might cause issues for other plants you wish to maintain or add to that spot.  

If you're removing non-native plants (whether invasive or non-invasive), determine if they had been providing any broader environmental function despite being non-native.  Should that affect your choices in determining which native plants you replace them with?  For example, it you're removing an over-abundance of invasive European sweet cherry trees which have colonized your property, it might be a good idea to make sure you are replanting native (or even non-native, but non-invasive) spring flowering alternatives to support the native pollinator species which had been utilizing the abundant blooms produced by the cherry trees.  You may also want to plant summer fruiting species which provide food for frugivorous birds which had been benefiting from those summer crops of cherries.  To be blunt, some of these invasive plants have become so wide spread precisely because we have native animal species which benefitted from them and who regularly move their seeds around!  Simply removing invasives and replacing them with natives is too simple of a strategy.  It's far better to put some thought into making sure your end result is in improvement over what you started with, not a step backwards.  

Let's say, you cut down an invasive cherry and replace it with a native Douglas fir tree.  Douglas fir provides nutritious seeds for our native Douglas squirrel as well as habitat for various birds, connections with native fungi, etc.  That sounds like an upgrade right?  Well, perhaps not.  Our native Douglas fir is already incredibly abundant and due to its utility in the production of lumber, is already planted in many areas at concentrations which are so great that they do not allow for much ecosystem balance.  Sure, plant a Douglas fir if you would like, but do so because you want it there, not because you think you are improving the ecosystem function of your space.  Since some of our top invasive species tend to be fruit bearing (cherries, blackberries, ivy, English holly, English hawthorn, apples/crabapples, etc.), consider including a diversity of native (and/or non-invasive) fruit bearing species when determining plants to add to your garden.  Afterall, the more native and/or non-invasive food sources that are available to native animals, the less they will need to rely on and move around seeds from the invasive ones.  

This isn't just about fruiting plants though.  Many seeds can be important food sources to local fauna as well.  If you're replacing plants which had been producing nutritious seeds or any other plant parts which were supporting local fauna, you should consider making sure that the native plant selections you add into your property can make up for what you are removing.  That could mean plants which produce hollow stems for overwintering insects, those providing protective nesting sites for various small critters and even plants which draw in and support a lot of bugs which feed off them and by extension create more food for bug eating animals.

That's not all though.  Let's say you found a spot where a native species is growing and looking super healthy.  You notice that that location is very similar to a spot you have in your own garden.  Perfect.  That should mean that you really can just plant that species in your own garden now and it'll just take care of itself with zero effort from you!  Not so fast.  That plant likely grew from seed in that spot, and had siblings which did not make it.  What you don't see is how many years that plant may have just puttered along slowly before finally establishing a broad enough root system to really look like something great above ground.  When you plant that species in your garden, the conditions may very well be nearly identical to where you saw it in the wild, but because you are already starting with a plant that's quite a bit larger than a seed, that plant has nutrient and water needs which may or may not be adequately supplied by the volume of roots which are able to fit into the pot it is growing in.  It may be that for the first year or two, some supplemental watering could be important to its survival even though it's technically adapted to our summer dry climate.  It may also benefit from feeding, be that from fertilizer or the slow release of nutrients from decaying mulch.  Eventually, it truly can become very low maintenance once it has settled it, but if you just plant it and forget it, it will be hit or miss.  This is no different from when you're planting non-native plants. 

I've said a lot already, but there's still more...

Humans have successfully reached all corners of the earth.  This is not new.  Humans are a part of nature and throughout the world, have been interacting in various ecosystems throughout the evolutionary history of those ecosystems.  Therefore, a look, but don't touch philosophy doesn't make sense.  There are many human activities which can benefit native plants, when they are done with mindfulness.  We are currently suffering the consequences of trying to keep nature too pristine with worse and worse wildfires as a result.  If we were to do the opposite and encourage not just more frequent small wild fires, but also activities like opening up areas where growth has become too crowded via manual methods like selectively thinning native trees and removing lower branches to allow more light to reach the understory and support more native diversity below.  This activity would not only support more native diversity within local ecosystems, but will also help ensure that when fires do come through, they won't burn as hot, or as easily spread to the tops of trees which will allow for much more survival and faster regrowth of plants after the fires have passed. 

People, and animals (and in some ways the plants themselves) have been moving plants around since before recorded history, and many plants which are considered native on multiple continents are actually the same species as each-other, or in some cases diverged into separate, but sill very closely related species.  If a single species is native all throughout the northern hemisphere, that doesn't mean that it evolved independently into the same species in many different locations.  It had to start in one of those places and then spread from there.  In every place in the world, there are plants (and animals) whose ancestors did not always exist in that exact location.  It's tempting to over emphasize preserving ecosystems based only on the species we documented to have existed there prior to recorded history, but quite fortunately for the earth, this seems to be a modern phenomena.  If there had been a species like us trying to stop species from moving around, hybridizing, or otherwise evolving their way into habitats they had not previously existed in going back to the beginning of time, life on earth would be pretty darn simple.  

If you've managed to read this far, I hope you will be understanding my point.  We are part of nature.  We should interact with nature.  Plant native plants because you appreciate how each one is special and to encourage them and use them to maintain or improve diversity in local ecosystems.  Just don't plant native plants because you think they're the cheat code to a zero effort garden.