Weeds in Perennial Beds

They seem to pop up everywhere – weeds.  New beds, old beds; it doesn’t seem to matter.  At this point in the season, a little moisture encourages growth of tons of weeds.  Seeing these weeds makes you wonder several thoughts.

  1. Where did they all come from?
  2. Why are they growing as well or better than the perennials?
  3. (of course) How do I get rid of them?


First one.  The soil, for sure.  Weed and soil scientists tell us that there are between 10,000 and 40,000 weed seeds in the average cubic foot of soil.  That’s a lot.  So, they’re already there, just waiting for the sun and moisture.


Second one.  One of the adaptations of the more vigorous weeds such as prostrate knotweed and large crabgrass is their tenacity and capacity to be prolific.  It’s hard to manage these pests, but one of the steps for control is acceptance of their ability to populate a flower bed.


Third one.  Fortunately, there are several effective methods.  Most grassy weeds can be sprayed with a product containing the active ingredient fluazifop with no damage to the desirable plant.  Be sure to double check the product label to make sure that the perennial flower is listed as a tolerant plant.


Mulching is another effective weed control method.  A thin (2 inch) layer of wood chips or similar organic plant based material will suppress a great deal of undesirable weed growth.  Finally, hand pulling, especially after a rainfall event or watering is a great way to directly reduce the weed population.  Each of these methods have pros and cons, but they key to control is persistence.

John Fech
Horticulture Extension Educator at Nebraska Extension
John Fech is a horticulturist with the University of Nebraska-Lincoln and certified arborist with the International Society of Arboriculture. The author of 2 books and over 200 popular and trade journal articles, he focuses his time on teaching effective landscape maintenance techniques, water conservation, diagnosing turf and ornamental problems and encouraging effective bilingual communication in the green industry. He works extensively with the media to extend the message of landscape sustainability, making over 100 television and radio appearances each year.
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