Plants for the garden: native vs. native enough

It's clear that growing native plants is a good thing. The benefits for humans are many — they feed us, filter our water, replenish our soil and sequester carbon. They are tough and adaptable plants that bring beauty and ease to our lives and gardens. More crucially, wildlife depends upon their flowers, foliage, fruits and seeds for their very survival.

Still, it's surprising how quickly the scene grows murky. What exactly is a native plant?

Native plants are defined as those that occurred naturally in the place where they evolved. Some people will go further to add "unaltered genetically by human activity." (More on that in a bit.)

Then there's that term "wild." Think of the ubiquitous orange ditch lilies, originally from Asia, that escaped the garden gate and now adorn our roadsides. They may have gone wild but they aren't native.

Here in Minnesota, I grow a patch of California poppies out front to remind me of my home state. Many seed packets or catalog descriptions will tell you that California poppy is a native plant — without further explanation. That's the problem with a big country like the United States when we talk about what's native and what isn't. You can't paint things with such a broad brush. Those poppies are native to the Western U.S. but not to here.

A delicate orchid on a stream bank in Tennessee or a scrubby sage on thin, rocky soil in Colorado may be able to exist only in that tiny ecosystem with a set of uber-specific growing conditions. So when you call a plant native, you not only have to ask "native to where?" but also "native to what environment?" What's native to a marsh in Minnetonka may not be native to the woods around Waseca.

What does all this mean for your front yard? When you look online or visit garden centers you'll see lots of excited marketing about native plants. It pays to educate yourself before you plant.

Here are the inevitable pros and cons. In the positive corner, hopefully, people will be enthused about and use more of these easygoing plants in their gardens, thus reducing or eliminating the need for fertilizers and pesticides, even lowering water usage. Simply creating more plant-rich landscapes in our comparatively barren yards (I'm talking those one-lawn, one-tree and three-bush yards) can go a long way toward helping to stem habitat loss for pollinators and other wildlife, not to mention the beautifying effect.

On the other hand, sometimes in selecting for one unique trait, the plant breeder may sacrifice others, resulting in changes to the flower structure, pollen quantity/quality or leaf chemistry that make the plant inedible to the wildlife that depends upon it. For example, the nectar might be absent or inaccessible to a bee, or the leaves might change to the point that a caterpillar won't recognize them as food. Such alterations are significant to insects that are specialists, meaning they depend upon a single plant source to survive.

Some of the new native cultivars are sterile; although tidier, they don't produce seeds for wildlife to eat. Also because these cultivars are cloned through vegetative propagation, genetic diversity and adaptability is lost.

At present, it's hard to know which plants may be affected, and which not at all. There are a few research centers studying this issue, but so far, there is no hard-and-fast rule to say which plant retains its original habitat value. Often the only way to know is through careful observation in your own garden.

Before adding to my garden, I ask that a plant earn its spot of real estate. First, it has to thrive in my garden conditions, the right plant for the right place. Then I consider native possibilities whenever possible, but I also think about how the plant will function for myself and wildlife. Will it provide food in some form? Can it provide shade, shelter or nesting sites? Does it discourage weeds, erosion, pollution?