Why using native plants in your landscape design is important.

Week Seven:

Native Plants Conference

This was a busy week on Monday and Friday at work. Out of town business guest were here and much had to be accomplished to prep for meetings which would take place throughout the week.

This week I also traveled to Cullowhee, North Carolina for the 30th Annual Native Plant Conference. I had the opportunity to attend this conference because of a scholarship which the conference awarded to me and a few other individuals.

I must say this, the conference experience, more specifically speaker Doug Tallamy had a profound influence on my appreciation for native plant specification in design. During his first general session talk, and much of his second session, Doug related the importance of native plants and the insect world to well…just about everything. Since plants are the first level where the suns energy is absorbed, it is essential that we have plants.

So, one would naturally assume that Landscape Architects are designing highly performative landscapes since most designs included vegetation of some kind. I even assumed so myself. As it turns out this is not the case. Simply designing a landscape with vegetation does not ensure that it is highly performative. Doug began explaining that all plants, as most of us learned in ecology class, exist as part of a food web. In the most basic way, think of a food web like this:

            Plants absorb sun’s energy.

            Insects eat plants.

            Small animals eat insects.

            Medium sized animals eat small animals.

            Large animals eat medium animals.

            Man eats everything including the kitchen sink.

In a food web everything depends on the plants’ action of absorbing the suns’ energy. Without this action plants will die and there will be no food. Here’s the trick. Animals don’t all eat the same thing. I am not referring to the most obvious differences like giraffes not eating zebras. I am referring to situations such as birds and insects not eating the same types of plants. The plant world fights to stay alive by becoming pointy or bad to the taste.

Ok, so here’s the application to landscape architecture. LA’s are specifying plants for nearly all of their designs. The problem is that these plants do a poor job of supporting the local and regional food webs. All of the animals in an area have been created to and have adapted to eat the plants of the region. This trait is known as specialization. So as designers actively/or passively choose plants from foreign regions, food availability diminishes from which the local animal population can feed.

Let’s have an example. One of the most popular plants in the Southeast is the Crepe Myrtle (Lagerstroemia indica). I, as many of you, would assume that this plant can sustain animal life such as caterpillars, birds, deer, and many other herbivores. As it turns out, the beautiful Crepe Myrtle can only support three species. That’s not too bad, right? I mean, three is better than none. Let me put this into perspective as Doug did at the conference. We are replacing native plants such as the oak tree to make room for these ‘pretty’ species. So the questions is really what is the cost (?), not what is the gain (3).

The Oak tree (I believe he had a specific species, I just didn’t write it down) supports over 500 varieties of species. Holy Crap! This significantly changes one’s perspective on what a performative species is. Doug has published many of his findings such as this one in his numerous books and articles.

‘So what,’ you might be saying. “Why do I as a landscape architect have to be interested in providing the most beneficial tree or shrub or landscape?” Earth’s surface is quickly being altered by man. Many cultures are creating vegetation deserts and fragmented areas which will have the previously mentioned effects on animal life.

Solutions to this ‘huge’ problem are simple and easily obtainable. The landscape architect can make a difference by creating wildlife corridors, planting native species, designing wildlife habits, and more. I am not saying that exotics are the devil or that each of these design ideas must be implemented every time to the fullest extent. My point is that little steps in the right direction add up.

Look for ways to incorporate native plants into your design by replacing one of the exotic plants on your palette with a native plant. The rest is up to you. Landscape architects are quickly realizing that we do not design in an ethical vacuum. Our actions always have consequences. What will you choose?