Establishing Perennial Cover

Establishing Perennial Cover

By Kent Boucher

Have you ever noticed how much easier it is to destroy than it is to build something great? It probably has something to do with the law of entropy, everything degrades into a state of greater disorder over time. This is easy to see when an old farmhouse gets introduced to a wrecking ball, and it’s evident too when considering the history of our native perennial plants here in Iowa. Thousands of years of geological, meteorological, and biological cause and effect blanketed the heart of our continent in deep-rooted, diverse plant life that was all but erased within just seven decades. Getting it back won’t be easy, but here’s how.

Step 1: Preparing The Ground
Nature abhors a vacuum, and this is true when it comes to bare dirt. Through years of terraforming activity, Iowa has replaced its native vegetation with a seemingly endless number of invasive plants. With this new competition on the landscape, re-establishing a healthy stand of native perennial plants begins with removing the invasive plants, especially invasive grasses. Unfortunately, this is a process many land managers only get half right. I say this because they only kill off the undesirable plants once before planting their perennials. The problem with this is there is a seed bank from the nonnative plants existing in the soil that is waiting for an opportunity to germinate and when the first kill-off takes place these weed seeds get their chance and rapidly take the place of their parent plants and establish themselves within the new planting, greatly diminishing the quality of the stand. This problem can be greatly mitigated with a double killing of the unwanted vegetation. The most efficient way to achieve this is with a herbicide treatment first in the mid-late spring and then again after the late summer/early fall rains bring about a fall green-up. With both cycles of weed competition being eliminated the new planting of native perennials will have the best chance to be the primary occupants of the ground.

Step 2: Preparing The Ground
If you follow the land management community at all, you will be familiar with a friend of mine named Skip Sligh. Skip has served as an excellent example showing how anyone can pursue land ownership, and how anyone can transform their land into a hunting paradise. A point of emphasis that I have heard Skip talk about quite a bit is the importance of knowing what the soil has and what it needs before seeding. With the weed cover removed from the ground, several soil samples for testing should be easy to collect. Once the test results are complete, the necessary fertilizers can be added to the plot and the new plants will have all of the nutrition they need to provide a healthy stand of habitat.

Step 3: Choosing The Right Seed
Iowa is what it is because of its soil and climate. These two qualities have made our state one of the most productive regions on the planet. Knowing this can mislead us into thinking that all seed will grow equally well within our borders. Natural selection has honed the traits of our native plants to match the ecosystem conditions where they come from. In the seed industry this is known as ecotype matching seed. Planting seed that doesn’t match a property’s ecotype doesn’t mean that it won’t grow there, but it does mean that it’s probably not going to grow as well as the seed that’s adapted to that ecoregion. The best way to ensure that your seed matches your ecotype is to know where it originates from. A good seed producer/vendor will be able to tell you the origin of the seed you are purchasing. Another thing a good seed vendor will be able to help you with is the proper seeding rate for your plot. Research shows that an equal seeding rate for grasses and forbs establishes a perennial stand that can better handle the pressure from invasive plants that will want to regain control of the plot. Find a good seed company, and you’ll have good seed.

Step 4: Understanding Planting Depth
Another major mistake made by land managers happens during planting. In cornland, we are all trained to plant seeds over an inch and a half deep. But when it comes to native grasses and forbs this practice doesn’t work. Instead of being planted deep into a seed bed, these species are designed to be seeded very close to the surface by wind, water runoff, and animal dispersal. With that in mind, seeds should be planted at about 1/8 of an inch of depth in the soil. Some professionals recommend a depth of 1/4” which can work, but plantings that are deeper than this will result in a failed seeding. This is most likely to happen when using a drill that’s set too deep, or if planting into freshly disturbed soil (from a recent discing or tilling). With the proper depth in mind the seeding can be done through broadcasting by hand, drop seeders, air seeders, hydro seeders, or native plant drills. Follow up the planting with a light cultipacking or attach a drag harrow behind your seeder to ensure sufficient seed to soil contact, and to help protect the seeding from seed eaters and wind and water runoff. A top-tier Iowa-based seed producer, Hoksey Native Seeds, sells a Native Seeder that has a drag harrow attached to efficiently serve that purpose.

Step 5: Planting Time
A unique trait that many perennial forbs have is that they require a period of cold stratification to bring the seed out of a state of dormancy. Hardcore prairie enthusiasts often achieve this by using their refrigerator and some kind of moist matrix to encase the seeds, but for deer hunters and land managers there are enough other chores and hunting responsibilities on our plates that it’s best to let nature do the work for us when possible, so I recommend timing your ground prep work (use the timeframe I mentioned earlier in the article) to be ready for a dormant seeding in early to mid-December. This will ensure that the seed doesn’t germinate before a killing frost and it provides a cold, wet environment for stratifying the seed so a maximum number of forb seeds will germinate when all of the grass seeds do in the late spring. This is critically important for diverse plantings, such as pollinator mixes. If dormant forb seeds are planted in the warm season, they will have a long wait until the following spring to complete their stratification period. This extended time laying in the soil makes them more susceptible to predation and other environmental threats, but it also allows for grasses to get an upper hand in the plot and crowd out the forbs when they finally get a chance to germinate.

Step 6: Maintenance
One of the best, and most obvious advantages to planting perennial cover is that it doesn’t need to be planted every year. In fact, well-managed stands can stick around indefinitely. That’s the key, “well managed” which means maintenance. The best maintenance practices can be summed up with mowing, hoeing, and burning. The first growing season for a perennial plot is going to look very poor. There will be annual weeds, and very little evidence of the native plants showing up in the stand. This is because perennial plants put most of their initial growth energy into developing their deep root systems.

Although it may appear that they are not germinating well, they are growing below the surface. While these native plants are establishing themselves, the annual weeds will attempt to regain an upper hand. Well-timed mowing is the best way to prevent them from going to seed without damaging the planting. For the first year of growth (assuming it was a dormant seeding) mow once in June, July and August.

For the second year of growth mow only twice, and by year three your stand should be well established. At this point, weed management becomes a spot treatment practice. Look for invasive grasses such as smooth brome, reed canary, or Kentucky bluegrass to encroach on the planting, and other noxious forbs as well like wild parsnip, birdsfoot trefoil, and sericea lespedeza. Either dig them up or spray them with herbicide to keep them from taking over. The same rule applies for tree encroachment as well. Forests swallow up prairies so remove any trees trying to establish themselves within your stand. Finally, after three years of growth, the prairie will be ready for a burn. Most land managers choose to burn in the spring, but this is only best when invasive cool-season grasses are the primary threat to the stand. If maintaining prairie diversity is the primary goal, a fall burn is the best option. The challenge with this is the surrounding crop fields and timber can be very dry in the fall so waiting until after the crops in the area are harvested, and waiting for the appropriate burning conditions are critical for attempting a fall burn. I also suggest rotating sections of the prairie for each burn year so there is still plenty of perennial habitat left for the wildlife and the hunters to use.

Planting native perennial cover on a hunting property is a wise investment that brings many benefits beyond hunting value. The perennial cover that once blanketed much of the continent was destroyed much more quickly than it was established, and the same holds true for a tallgrass bedding area on the back 40. However, with the correct seed, diligent ground preparation, smart planting strategies, and dedicated maintenance, that back 40 will be one of the best pieces of habitat in the county.