- December 28, 2015
Have you had enough of all the mowing, watering, and chemical applications needed to keep your traditional turf short, green, and weed free? Are you interested in improving your yard to provide habitat for birds and other wildlife but still want to keep a grassy open area for recreation? Perhaps it is time to go with a native approach.
Native lawns are created with short and slow growing native grass species that require less irrigation and are more likely to be resistant to weeds, pests, and fungus. The initial installation and establishment of the grass is a crucial part to the success and sustainability of a native lawn. Below are some guidelines to help make sure your lawn conversion is a rewarding experience from the first shovel to the last mow.
Plan the site
A native lawn can have the familiar look and feel of a traditionally manicured turf or it can be integrated into a larger garden design that will encompass the whole yard. Whether you are starting with an existing lawn or the bare dirt of new construction, a clear plan of your yard will consider where lawn areas are the most useful or enjoyable and begin by converting those particular areas to native grasses.
The remaining areas could be removed and replaced or filled in with beneficial native habitat like wildflower meadows, perennial beds, or maybe a pond or rain garden depending on your terrain. Developing a planting plan for the site will give you the size and location of the native lawn so you can begin selecting native grasses suitable for the specific light and soil conditions.
To determine which native grass species will be most successful, collect some specific information about the site. Using a simple test kit like the one shown above, you can easily determine the pH of the soil. Also, look into the type of soil you will be planting into. Is it sandy or dense with high clay content, mostly mineral, or rich in organic material? Squeeze a handful. Does it stick together like clay, or fall apart? An easy test guide, created by the Colorado State University Master Gardeners program, provides a few simple test like this you can do to determine the type of soil you’re working with. Check if the soil is fairly dry or generally moist. Does it drain well, and how often will it get rain or other irrigation? Most importantly, take note of how much sun the site receives. Most grasses do prefer a fair amount of sun but there are many native species that will perform as well in the shade.
The information you collect will also be useful when considering other plants you may want to include. Often, native lawns will have an ornamental style and will incorporate a number of plant species from mixed grasses and wildflowers to small trees, cacti, mosses, and other unique vegetation.
Select the species.
After defining the growing conditions of the native lawn site you can begin selecting the species that appeal to your preferences and creative vision. There are a number of regionally native grasses that will give you a selection of color, feel, and manageability and many of them are commercially available in either seed form, plugs, or rolled sod. Read Native Grasses for your Native Lawn for a greater selection of the most common and widely used varieties in native lawn installations.
Species selection will be influenced by which available forms can be acquired, and what is best for your particular project or space. Seed is generally the best choice for very large areas. It can be broadcast at different seeding rates for the desirable density and coverage and also has the advantage of faster establishment. Sowing grass seed requires a well prepared seedbed free of competing vegetation and will need the most attention the first season while germinating. Grass plugs are stronger and more forgiving but require more initial labor than seeding and may take longer to fill in.
Harvest Your Own Native Grass Seeds
Depending on your location (and your ambition!) it may be possible to harvest your own seeds from mature grasses growing nearby. Enthusiasts have collected seed from power line right-of-ways, near train tracks, wild meadows, and grassland areas. Going this route requires an intimate knowledge of the plant species you choose to propagate. You must be able to correctly identify the grass species and know when to harvest the mature seed. You will also need to thresh the seed to remove the chaff or husk before it will be usable. There are a number of ways to accomplish this, from taking your harvest to a local facility or doing it yourself by grinding the seed heads through a sieve and gently blowing off the excess chaff. Nativeseeds.org provides a quick guide to help process and store the seeds.
After processing the seed to remove the chaff, it will often need to be scarified or cold stratified to promote germination. Scarification simulates animal digestion and includes sanding, scraping, or soaking the seed in an acidic solution. Cold stratification simulates overwintering in the soil and can be done by sowing seeds in a tray of growing medium and refrigerating for several months through the winter. In the spring, put the trays out in the sun, keep watered, and you will have large grass plugs to transplant in the early fall.
Prepare the ground
You’ve chosen the most appealing and appropriate species to create your ideal native lawn, now give them the best chance at survival by doing a little ground work. Whether you have acquired bags of seed, plugs to plant, or sod to unroll, removing the existing vegetation will be the first step to eliminate competition and establish the new transplants.
If you have a traditional lawn of dense sod you may be able to remove it, in rolls, with a sod cutter. If the grass is not thick enough for sod it should be tilled into the soil with a rototiller, repeating every couple of days for a week to ensure the tilled vegetation does not set root and regrow. The most ecological solution, however, is to smother the lawn underneath a plastic or biodegradable layer, retaining soil structure and adding compost as the vegetation decomposes underneath. To smother, begin in the spring by saturating the existing lawn with water, then cover with 20 layers of newspaper and approximately six to eight inches of fine mulch. Leave this cover for about three to four months then plant directly on top of it in the fall.
Alternately, you could cover the existing lawn with a black or clear plastic and seal around the edges with dirt. Over the summer, a greenhouse effect will cook the vegetation, the seed bank, and many pathogens that may be in the soil. Both of these smothering methods will add organic material to the soil and require less amendments than a full sod removal.
If you are starting with bare ground, you may want to cycle through the seed bank in the soil. Pull any weeds that are present then water, wait a week, and destroy any new weeds that germinate. Pull by hand or scuff the surface with a rake on a hot, dry day to cull the new sprouts. You may need to repeat this process several times before the seed bank is depleted.
After the existing vegetation has been removed, till the soil about 6-8 inches deep –good drought tolerance depends on deep rooted plants– and mix in any amendments like sand or compost for structure, or lime to raise the pH if need be. Level, flatten and smooth the tilled soil with a gravel rake and then a roller to give a consistent surface structure to the newly prepared bed. This will even out the germination and provide a more uniform planting. Be prepared to plant immediately. Waiting more than a couple days will increase the chances of wind-blown seeds colonizing your bare plot before the native grass does.
Plant your grasses
Whether you are sowing seed or planting plugs, seasonal timing can be one of the most important aspects to the successful establishment of a new native lawn. Plant when conditions allow the best germination of the seed without putting the sprout at risk. Moist weather and moderate temperatures are ideal. Spring planting may be fine but there may be a risk of losing young plants to summer heat or to competition from annual weeds. Planting in the fall is ideal for most species and locations. It allows the grass to germinate and set roots before winter and gives the sprouts a head start against any weeds popping up in the spring.
Seasonal timing of sod placement is much less critical and can be done anytime during the growing season, although the cooler temperatures and wetter climate of the spring and fall may be more ideal if your summers are very hot and dry. Sod is convenient and practically instant but is less common in native grass replacement and may be difficult to acquire.
The next few years
In the first season, immediately after planting, it is important to maintain a consistent and moderate moisture level. Slow, light irrigation that does not puddle, pool, or run off will penetrate deep into the ground to encourage roots to follow, while minimizing erosion or seed washout. Cover seed with a loose layer of straw to help minimize erosion, shade the delicate sprouts from intense sun, and protect them from herbivory.
A well timed mowing schedule is also important to ensure the establishment of your native grasses. In the first year, mowing will be primarily used to control annual weeds from seeding and outcompeting your plantings. Mow at a high setting when weeds are flowering to prevent seed heads from forming. If there is a lot of cut-off plant material, carefully rake it up and remove or it can smother the new spouts. As long as these annual weeds do not go to seed the perennial grasses will continue to fill in.
In the second year, let the native grasses grow to maturity and produce seed once per season. This produces a thicker planting and increases genetic diversity across the lawn making it more resilient to environmental pressures. Warm season grasses flower and produce seed at the end of their summer growing season, while cool season species are productive in the spring and fall when temperatures are cooler and will flower late in each season.
Over maintenance can be difficult to let go of. Allow the lawn several seasons to become established before deciding whether to use fertilizers and other maintenance measures. Native lawn failures tend to be associated with inadequate soil preparation, over-mowing, and high use of water and fertilizer input. A native lawn is accustomed to growing without the additive help; so let it grow!