Seed Mix Establishment: Post Planting Maintenance

YEAR ONE
Weed control during the first growing season is essential. The perennial prairie seedlings grow slowly, and are easily out-competed by the faster growing weeds that will inevitably germinate.

  • Mow your prairie about once a month during the first growing season. The actual mowing frequency will depend on rainfall in any given year, actual weed density and height.
  • Mow the entire planting when weeds reach the height of 12 inches.  As a general rule of thumb, anything that grows taller than 12 inches in the first year is most likely a weed. Taller weeds shade out prairie seedlings. Mowing the vegetation at six inches will cut back taller weeds, while leaving the shorter prairie seedlings unharmed.
  • To mow, use a string trimmer or weed eater on small areas. On larger areas, a flail mower is the best choice. Flail mowers chop the weeds as they are cut, instead of laying the cut weeds on top of the prairie seedlings. If a flail mower is unavailable, a rotary mower or sickle bar mower may be used.
  • In the first season prairie seedlings rarely grow taller than four to six inches, with the possible exception of the Black Eyed Susan. As difficult as it is, we recommend cutting all vegetation, including the tops of the Black Eyed Susans. Cutting will not kill the Black Eyed Susans.
  • Be sure to mow weeds before weeds set seed, to prevent further infestation.
  • Although tempting, we do not recommend pulling weeds, as this will disturb or destroy the developing prairie seedlings.
  • At the end of the first growing season, leave the dead vegetation and or stubble standing, this helps to catch winter snows which helps insulate the soil seedlings and reduce winter frost heaving.

YEAR TWO
During the spring of the second year, mow the standing residual vegetation as close to the ground as possible in mid spring, and rake off any cuttings. Mowing in mid spring helps to set back non-native cool season weeds and grasses such as Quackgrass, Bluegrass, and Bromegrass etc. Timing is very important when mowing your prairie. The optimal date for mowing can vary as much as a month in any given year, due to the differences in weather. However, we can use plants as our calendar to ensure optimal timing. The best time to mow most prairies is when the buds of the Sugar Maple tree (Acer saccharum) begin to break open in spring. This usually will occur sometime between April 1 and May 15, depending on your location and the weather in any given year. This is usually about the time we are mowing our lawns for the first time.

  • Removing the vegetation and raking the vegetation encourages soil warming, which triggers the warm season prairie plants to break dormancy.
  • If Biennial weeds such as Sweet Clover, Burdock, and Wild Parsnip etc., appear or are a problem, mow again at approximately 12 inches when weeds are in full flower.  Make sure to mow the weeds before they make seed!  Expect this second mowing for controlling biennial weeds to occur in June, depending on your location.
  • Do not mow after new plant growth has reached one foot or taller, as this could damage your prairie plants.

YEAR THREE and BEYOND
Burning / Mowing
Beginning in the spring of the third year, your prairie can be burned for the first time to maintain its diversity and vigor.  Burning in mid-spring helps to set back non-native cool season weeds and grasses such as Quackgrass, Bluegrass, Bromegrass etc. By waiting until the undesirable plants have initiated spring growth before burning, the fire will destroy their new growth and set them back, favoring the warm season prairie plants, most of which are dormant under the soil.

Burning removes plant litter from the previous year’s growth and exposes the soil surface to the warming rays of the sun. This encourages new plant growth and increases flowering and seed production of native flowers and grasses.

Timing is very important when burning your prairie. As with mowing, the optimal date for burning can vary as much as a month in any given year, due to the differences in weather. However, we can use plants as our calendar to ensure optimal timing. The best time to burn prairies is when the buds of the Sugar Maple tree (Acer saccharum) begin to break open in spring. This usually will occur sometime between April 1 and May 15, depending on your location and the weather in any given year. This is usually about the time we are mowing our lawns for the first time.

  • If you cannot or do not wish to burn, we recommend mowing all vegetation to the ground at the same timing as described above. Mowing is about 60% effective at controlling weeds compared to conducting a burn.
  • Dry prairies (sandy soil) should be burned in the late fall after most of the native plants have gone dormant, but the non native grasses are still active. Burning in very early spring also can be done successfully on dry prairies.
  • It is recommended that you divide your prairie into “management units.” Burn or mow one half every other year, alternating from year to year so that each half is burned once every two years. This helps prevent invasion by woody plants, as well as cool season weeds. Burning or mowing less frequently than every other year can result in trees gaining a foothold in your prairie. Burning every year is generally not recommended, as it tends to increase the dominance of warm season prairie grasses and certain prairie flowers.
  • Leaving unburned sections of your prairie preserves overwintering butterfly, moth and other invertebrate pupae and eggs so they can re-populate the ecosystem that year. These species would otherwise be destroyed by burning.
  • Do not burn or mow after new plant growth has reached one foot or taller, as this could damage your prairie plants!
  • Many Ground nesting birds build their nests in spring and burning or mowing will destroy nests. Mid-spring timing of the burning or mowing maintenance leaves sufficient time for birds to re-nest and successfully raise their young.
  • Burning or mowing every three years helps to create varying conditions from year to year, maintaining maximum plant and animal diversity.

Up next: What to Expect the First Three Years


Designed for areas of 1000 square feet or more, we’ve designed 24 native seed mixes for virtually any soil or condition:  http://www.prairienursery.com/store/seed-mixes


Establishing a native plant seed mix is a long-term investment in your landscape, which requires careful planning. When questions arise a one-on-one conversation may be the best way to get the information you need. Don’t hesitate to call us at 800-476-9453, Mon. – Fri., 8am – 5pm, CST. Or, email us at cs@prairienursery.com. We are happy to discuss individual complexities in order to make your planting a success.