05 February 2014

Is My Garden Native Enough?

Over the past few months, I’ve been getting freaked out that my garden doesn’t have “enough” native plants. I’ve been looking around and all I can see are non-natives that were either planted before I arrived, or in fact, were planted by me. The latter in particular have been making me feel embarrassed or irresponsible somehow. But let it be known that I too fall prey to that urge at the garden center to pick up random plants that look nice or captivating in some way.

For those of you who’ve been following the blog for a while, you know that I feel very strongly that I ought to use plants native to this region. This is important to me for a number of reasons, including supporting our struggling native wildlife. As Doug Tallamy points out in “Bringing Nature Home,” native plants support native bugs which support native frogs, birds, lizards, and ultimately, humans. Of course there’s also potential reduced maintenance, water use, sense of place, and many more reasons.

Collecting Data. Because Science.

OK, so back to freaking out and judging myself, neither of which are healthy are they? Before I began spontaneously ripping out all of our non-natives, beating like tell-tale hearts in my imagination, I decided to get more scientific about it. I wanted to find out if my garden really is heavily focused on non-natives, or if I was just perceiving that. So, I collected some data. I made a list of most of the plant species in the garden and classified them as:
  • Blackland prairie native. My garden sits closest to where this historic ecosystem used to be. We have deep black clay soils. Plant examples include little bluestem and giant coneflower.
  • Central Texas native. Austin sits at the convergence of several ecosystems, and plants clearly move back and forth among them over time. We aren’t far away from the Balcones escarpment, which is drastically different habitat. Blackland plants would also be considered “Central Texas natives,” but for my counting purposes, I’ve only given them one label. These plants are more Edward's Plateau-related and include cenizo and flame acanthus.
  • American native. These plants fall outside of Central Texas, but are native to Texas or other parts of the U.S. This includes plants like Arizona ash and bamboo muhly.
  • Non-native. These are just plain not native to anywhere in the U.S. Think: xylosma and Greek oregano.
Here’s my mostly full list of plants. (Caveat: I have not verified fully the exact native ranges of these species, and some of them, such as the Carex retroflexa var. texensis are cultivars, which complicates things.)

Here’s a little graph showing what I found:

And here’s what I happily learned from the above analysis:

Actually, Blackland prairie and Central Texas plants dominate my garden in terms of species richness. (Species richness is a simple count of how many species are in a defined region; in this case, my yard.) At the Grackle, we have 93 different species of plants total, 70 percent of which are native to this general area.

Species richness is distinct from species diversity, which takes into account things like relative abundance. If I were looking at diversity, for example, I would need to take into account that my garden has more than 50 individuals of Carex retroflexa and more than 12 Yucca pallida. There’s only one big giant Arizona ash.

Honey I Shrunk The Plants

Bottom line, I guess, is that sometimes what I see everyday, like the Arizona ash, the loquats and the xylosma, dominate my perception because they are, put simply, big. In reality, the overall garden is quite a bit more diverse.

But importantly, the way I see the garden may be how certain other species are perceiving my garden too. Perhaps some of the birds and bugs only “see” the giant ash and xylosma, of which they cannot utilize not at all. They fly through and don’t perceive much useful to them aside from a branch to perch on (which, come to think of it, has value too).

Ultimately, wouldn’t it be better if that Arizona ash were a tall sycamore or common persimmon? Or if those loquats were Texas persimmons and yaupons? Taken to a further extreme, that those bamboo muhlies were instead Indian grass?

Well, in fact, the answer is - for me - YES, but the reality can be quite different. It costs money and time to buy new plants and nuture them. It takes water, too. Some of these non-native plants provide other services, such as much needed shade (or a nesting or perching place). And then, it’s hard to draw the line. What exactly is native? How far away does it need to be from my house to be native? And really, who wants to be so dogmatic anyway?

It's For the Birds

Perhaps this is all to say that I still think it’s important for me to think about plant choices very carefully before committing to them. And it reinforces my wish that nurseries and home centers should not be stocking these species that have no place, no meaning, no purpose other than being pretty. Ultimately though, it’s really my responsibility as a consumer. If we all stopped buying nandina from Home Depot, they’d stop carrying it.

So, back to my decision making. My goal is to try to replace the non-natives as I can. I’m not going to do any major plant-ectomies at this point, but I plan to over time, strategically. And I definitely want to be more conscious of my decision-making at the nursery than I already am. I don’t want to drive myself nuts, but I want to be responsible.

Because mainly, I want to help the butterflies, bees, birds, lizards and snakes. They need it.


Reeves Clippard said...

There is a great saying from my in-laws that has become somewhat of a joke we've heard it so often, but is a relief to say "I've already forgiven myself." It's not an indulgence for bad behavior, but a reminder not to beat yourself up for not being the best all of the time.

Jaimie said...

I really am quite inspired by your garden, especially your commitment to native species. Non-natives can be okay (I do admit a certain infatuation with Pride of Barbados, despite being non-native and grossly overused in the Austin area).

We have removed sooooo many boxwoods and nandina from our new house. The yard was wildly overgrown, half-dead from drought, and just neglected in general. Sometimes it's hard to justify removing well-established plants simply for being non-native. I'm hoping to start adding native species back in when spring starts to come around.

At our old house we planted a flame acanthus that attracted the first hummingbird I had seen after four years in that neighborhood (as well as some native bumble bees).

TexasDeb said...

I too am inspired, and if I'm being honest it is at least in part with your ability to accurately identify everything in your planted areas. I've got things growing front and back I cannot identify. Clearly I have work there as starting point.

I made it my new habit for the past two seasons not to purchase or propagate non-natives. Any/everything I put in as new plant or replacement either one, has to get past the NPIN idendity/bouncer.

Because you are right - if we don't buy them, the nurseries won't keep carrying non-natives.

(Beautiful exception? Your loquats - they do support native wildlife abundantly! I'm forgiving myself already for those.)

katina said...

Now I need to go and make a list of everything I've got in my yard...though some might be hard to place like the giant petunia I have - it's not the standard Mexican petunia, it might be carolina petunia...