My Successes and Failures in Growing Native Plants
"Gardening is not for those who require the predictable." Anonymous
This is one of my favorite quotes, and there is nothing like sitting down to list my successes and failures to drive home the truth in this bit of gardening wisdom.
After almost 18 years of growing native plants and creating extensive native plantings to replace lawn, I would like to pass along some dos and don'ts based on my experience. At the same time, everyone's experience will likely be a little different so I hope you can adapt these bits of advice to suit your own needs.
What Doesn't Work
It is very easy to select my top three errors. This list is based on my experience since moving to northeast Tennessee in late summer 2006. My husband and I have been working for the past four years to convert about a one-half acre of mowed lawn to Tennessee native woodland and wildflower meadow.
A Superficial Site Assessment
It is easy to look out a window during a rain storm or to casually walk your property and think you understand the conditions in your yard. When it comes to stormwater runoff, there is no substitute for going out in a heavy rainstorm and thoroughly walking your property to see exactly where water is flowing or standing. Failure to do so can mean projects do not go as planned, and you will need to make after-the-fact corrections. For example, I placed a 600 sq. ft. rain garden at a great site for rainwater intake, but I failed to notice that it was located on a downhill slope from the houses above me. In a heavy rain, I had lots of water collecting in the rain garden inside the berm but I also had lots of water collecting outside the berm trying to get in.
A good site assessment also includes a close-up inspection of soil moisture and lighting. Failure to do so can mean plant failure. I set aside a large section of the front yard for shrubs and trees, but I did not go out during a rain storm and discover that the lawn hid the fact that standing water accumulated quickly in part of the site. We had to dig up a young tree one year later due to water stress and drag it across the front yard to a new drier location.
Failure to Understand Variation in Plants
If you have lived in more than one part of the U.S., don't assume that a plant species that did well at your old location will perform in the same way at your new location. If the plant species is an important component of your plantings, get to know how it performs in Tennessee before you use it.
In Wisconsin, I had relied on Virginia wild rye as the basic grass of my woodland planting. It was sturdy, green, very drought tolerant, and had beautiful seed heads. At my new home in Tennessee, I installed a large woodland area about 140 by 50 feet, and I promptly planted a large quantity of Virginia wild rye. To my dismay, I discovered that in Tennessee, Virginia wild rye is top heavy, very prone to wind-fall in a wind storm, and turns dry, brown by mid-summer. It is impossible to eliminate now that it has been established in such a large area, and dealing with it has been a struggle. My goal has been to try to totally remove it from the most wind-prone area and to greatly increase plant diversity in the other areas.
Native Plants in a Traditional Garden Style
This problem is an easy mistake to make. We are so used to having gardens of different styles-rock gardens, bulb gardens, lily beds, etc.-that it is easy to slip into this planting mentality without even realizing it. When I started planning my various native plantings, I prepared specific plant lists for each of the three wildflower meadows that I wanted to install. Each meadow had specific and unique characteristics. For example, I wanted my butterfly meadow to have only plants that got no more than 3 feet tall. This design technique may work with non-native ornamentals, but it certainly doesn't work with native plants. Seeds of native plants have evolved an amazing capacity to travel long distances, and it is part of the plants' ability to survive and quickly cover bare ground. In less than a year, I was pulling uninvited 4-5 feet native species from my butterfly meadow and wondering how in the world seed could travel that quickly from the rain garden on the other side of the yard.
If you want to insist on stylistically different beds on the same property, you need to be prepared to work to maintain them. Or, at a minimum, select plant species that will still be acceptable to you if they migrate to other planting beds in your yard.
Successes are always more fun to describe, and fortunately they are also part of the unpredictability of gardening. Here are my favorite successes.
When it comes right down to it, gardening with native plants in a natural style does look more uncultivated, and our society has a fixation with the manicured look of a mowed lawn or formal garden. I have had people look at photographs of my rain garden, and the first question they ask is whether my neighbors object. My beds may be colorful and weed-free, but they don't fit our stereotype of the cultivated yard. Part of the solution is promoting changes in people's attitudes, but part is also finding ways to make your beds look good. One of the best ways is neat edges on straight or curved lines. Find a way to make the edges of your bed clean and even.
I use several different techniques. One is to line the edge of the bed with 6 to 12 inches wide pieces of river rock and add an outer strip about 12-14 inches wide of crushed rock. Place these materials over a layer of weed-barrier landscape fabric. The crushed rock makes a great mowing strip and gives a nice clean line. Another alternative is wood chip mulch. Mulch the outer edge of the bed to a width of about 16-18 inches and use the mulch to keep lawn grass from encroaching into the plant bed and to keep native plants from encroaching into the lawn. Realistically, you will need to use a non-selective herbicide 3-4 times per year along this mulch strip to keep it plant and grass free, but a minimal amount of herbicide will go a long way. Then once a year clean up the edge with a shovel in those spots where you have lost your clean line.
If your bed isn't too large and the line is straight, you can use landscape timbers. Prepare the ground so that it is level enough that the ends of the timbers meet evenly. Drill holes in the timbers and pound in rebar to firmly anchor the landscape timber to the ground.
Simplified Seed Application
Most articles on planting native seed specify that the soil be tilled in advance, and sometimes there is even a warning not to apply seed over dead sod. But if you have hard clay soil and you are working on a slope, which describes many yards in Tennessee and particularly our yard, the thought of turning over the soil brings up dire images of large chunks of hard clay eroding downhill in a rainstorm. Tilling or plowing was just not an option.
I decided to try what Mother Nature does--drop seed on the surface. I assumed that most seed has been designed by nature to work its way down into the soil over time, and I further assumed that dead sod (sprayed with herbicide in advance of planting) would help hold the seed in place until it got started. I preferred to test these assumptions before I would try to till up hard clay. After having done three wildflower meadows, I can say that this technique works quite well. You do have to use about 25-50% more seed because the germination rate is lower, but that is a small price to pay.
Use of Annuals in the Seed Mix
Last year I tried for the first time adding annual seeds to my seed mix for a new wildflower meadow. I figured that annuals could act as a nurse crop to give the perennials some protection while they are getting started, and that they would give me some instant color in the first year when things are otherwise pretty slow. This effort succeeded beyond my expectations and produced some breath-taking color. I tried to use species that are native to Tennessee, and there are some nice ones. I used Indian Blanket or Firewheel, Drummond Phlox, Dwarf Red Plains Coreopsis, and Lemon Mint, plus Scarlet Sage which occurs close by but probably is not a Tennessee native.
I assumed that the annuals would re-seed and while they would not be dominant in the following year, they would be present. This is the second year of my experiment, and I am a little surprised to see that the annuals, while still present, are fairly sparse. So if you want annuals as an on-going feature in your plantings, it appears that seed needs to be added each spring provided there is still space for them.
When I am looking at lawn made up of a mix of grass and weeds and thinking about how I am going to plant the area, it is hard to imagine how much that site is going to change. Beginning work on my projects almost feels like an act of faith. But in a relatively short time, you can turn a mediocre lawn into either a colorful meadow filled with wild flowers or the beginnings of a shady woodland of trees and shrubs. Sometimes I look at before-and-after pictures of our plantings and am amazed at the change, and I am even more amazed that the work my husband and I did has produced that change.