Lawn Weeds

August 20, 2014
  • Field of Dandelions

Lawn Weeds

A weed is a plant out of place.  Seems like such a ‘nice’ definition for these little plants.  Weeds can be issues in many areas, but it always seems that they are the most plentiful in the lawn.  The key to knowing when to pull and when to spray depends on the weeds and time of year.  Unfortunately there is not a quick, all-natural weed control product that will cover all weeds however, prolonged use of a properly applied organic fertilizer program will reduce weeds, disease, and pests . It all comes down to proper identification of the weed and its life cycle. As a general rule, if you have less than 10% weeds in your lawn, you don’t have a weed problem!

Winter Annual Weeds

Henbit

Henbit

Winter annual weeds bloom in the spring, produce seed, and die all before the temperatures get hot. One of the more common winter annual weeds is henbit, which is the ‘pretty’ purple flower in bloom in the road ditches.  Henbit has scalloped leaves, a square stem, and little purple flowers at the tip of the stem.  These weed seeds germinated last year in September or October.  The little plants sat dormant throughout the winter just waiting for the right time to jump into flower and seed production.  Right now most people would apply a post emergent herbicide, products like 2,4-D, but it would do no good.  Spraying might make you feel better, but it can cause the plant to produce and drop its already mature seeds.  If the area isn’t too large, you can hand-pull these weeds.  Also, look at the density of your lawn in the areas where the weeds are located.  Is it thin?  You might need to figure out why the turfgrass isn’t competing with the winter annuals and a cultural practice change might be needed to promote grass growth and density in that area.  A soil test would be recommended if one has not been preformed. If herbicide control is needed, traditional preemergence herbicides should be applied in early September to control winter annual weeds.

Summer Annual Weeds

Crabgrass

Crabgrass

Summer annual weeds germinate in the spring, grow throughout the summer months, and produce seeds and die before winter.  One of the most common summer annual weeds is crabgrass.  Crabgrass is an annual grass that often fills into areas where the turfgrass is thin.  There are products that you can apply now to help keep the crabgrass problem at bay.  Crabgrass preventers, or preemergence herbicides, will help you in this fight against crabgrass.  These products will only work to keep seeds from germinating, or beginning to grow, not for plants that are already growing.  Crabgrass needs a minimum soil temperature of 50 to 55 degrees to begin germination.  Traditional preemergence herbicide or a natural corn gluten needs to be applied just prior to germination provide the longest period of control.  In most years, the optimum time to apply preemergence products for crabgrass are between the end of April to early May, roughly when the forsythia bushes are blooming. Remember that these products need to be watered into the soil profile for best control.

Perennial Weeds

Ground Ivy

Ground Ivy

Perennial weeds come back year after year.  The common offenders include white clover and ground ivy.  Ground Ivy looks very similar to henbit, but the control methods are very different.  Ground ivy also has scalloped leaves, a square stem, and purplish flowers, but the flowers are in the leaf axil, between the leaf and the stem.  Positive identification is key to the control method.  Since ground ivy is a perennial and comes back year after year, a post emergence herbicide will be needed.  If the product is applied now, the foliage might be burned back, but the plant will regrow.  The best time to apply post emergence herbicides for perennial lawn weeds is in October with a combination herbicide, like Trimec that contains 2,4-D, MCPP, and dicamba.  Natural weed sprays will not work on Perennials. These products will also work well to control other weeds like clover or dandelions in the lawn.

Benefits From Weeds

Dandelion benifitsBe careful and do some research before controlling weeds since some weeds can be very beneficial. White clover was considered an attractive and necessary component of healthy turf until the 1950s, and was often included in grass seed mixes. Clover takes nitrogen out of the air and makes it available to grass every time the lawn is mowed (the clipped off pieces of clover degrade and the nitrogen in them feeds whatever plants are around).  Without the clover you need to add fertilizers.  Dandelion, which literally translates into “lion’s tooth” in French, is rich in vitamin-A, C, iron and calcium and detoxifiers which explains its common inclusion in medicines. Dandelions can help strengthen bones, protect the liver, help with diabetes, eliminate deposits of toxic substances in the kidneys and the urinary tract, skin care/acne, weight loss, cancer, gall bladder, anemia, high blood pressure and a good source of fiber in your diet. So, because the lawn care company is keeping the lawn free of weeds they also need to fertilize because they’re killing all of the natural fertilizer. Organic fertilizers help replace all these nutrients on a neglected lawn.

With proper identification and timing, these out-of-place plants can be controlled.

Lawn Weeds Information provided by Elizabeth KillingerOrganic Facts, Mikes Organics Lawn Care and Omaha Organics staff.

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