Three questions were sent in recently by readers. The first is about bees in response to the article I wrote about orchard bees. The second question is about rubber mulch in response to the article Gladys wrote about mulching. The third question is about late fall lawn fertilization.

          Gladys and I really like to get questions and comments from our readers. It is much easier writing an article from a question than from what we think you would like to know. *************************************************************



          One of our readers sent in the following: “This question is regarding the column about bees.  George said that most bees are solitary creatures that live in a hole in the ground.  This really fascinates me, because recently my neighbors asked me about how to get rid of an apparent bee colony living in a hole nearby.  I was interested in the statement that they are completely non-aggressive and perfectly safe around even kids and pets.” 
          “This hole in our neighborhood looks like what you see when watching the sky around O'Hare airport.  If you stand and watch for awhile, it seems they are coming in, one after another, just like the airplanes landing.  Mostly I have seen the bees going in, during the late afternoon or early evening.  What can you tell me about this?  And how can you tell the difference between a more dangerous, stinging type bee and the type referred to in the column? Thank you in advance for your advice!”

          Since this question involved the safety of kids I e-mailed the response to the reader and am publishing the question and answer today. I am fortunate to have a number of very knowledgeable people as friends and associates that I can call on for assistance. One is Dr Marion Ellis , Entomologist at the University of Nebraska-Lincoln and head of the Bee Keeping Program who e-mailed me the following response to this question:

          “The social insects living in the hole in the ground are probably not bees at all.  They are probably yellow jacket wasps.  Their nests are very large and noticeable in the fall of year.  Vibration around their nest from mowers, weed eaters, kids running can trigger them to be defensive.  If a large nest is located where kids play, it should be exterminated or the kids should avoid the area until we have a killing freeze.  It is inadequate to simply put a toxin in the entrance as the nest may be 4-6 feet from the entrance.  The toxin will only trigger the wasps to make a new entrance, and it will often leave them agitated and defensive.  To exterminate a nest, one needs to locate the actual nest and introduce a toxin at night when all colony members are in the nest.  I get a dozen or more phone calls per day this time of year (early fall) about "bees" nesting in the ground, and they almost all turn out to be yellow jacket wasps.”

          If you want a positive ID in order to know if an insect is a solitary bee and therefore not very aggressive, or a social insect that should be avoided, take a digital picture of the insect and the hole, and take the pictures to your local County Extension Educator or to the Entomology Department on East Campus in Lincoln.

Copyright 2008




          One of our loyal readers wrote to me the other day with a question about rubber mulch. She had heard that one of the box stores was going to discontinue some of their wood mulch and start promoting rubber mulch made from old tires.  She said they are going to advertise it as “Environmentally friendly and safe”.  She also said they will be pushing it as “a Green thing because it would be recycling tires and would last longer”.  She concluded by asking “Is it a good thing that lasts longer and is it safe?”

          Dr. Linda Chalker-Scott , Ph.D. , Extension Horticulturist and Associate Professor, Puyallup Research and Extension Center , Washington State University, has written a very good article “The Myth of Rubberized Landscapes”. To read the whole article go to Dr. Chalker-Scott ’s web page at “” and click on “Selected Publications” on the right side of the page. Then click on “Horticultural Myths” at the top of the page, then scroll down to 2005 and click on the article about Rubberized Landscapes. While you are here you may want to bookmark this page as there are a number of very good articles available.

          In summary Dr. Chalker-Scott says, “It is abundantly clear from the scientific literature that rubber should not be used as a landscape amendment or mulch. There is no question that toxic substances leach from rubber as it degrades, contaminating the soil, landscape plants, and associated aquatic systems. While recycling waste tires is an important issue to address, it is not a solution to simply move the problem to our landscapes and surface waters.”

          The article also talks about the effectiveness of rubber mulch She says, “Rubber mulches have not proved to be particularly good choices for either horticultural production or landscape uses. In comparison studies of several mulch types, rubber tire mulch was less effective in controlling weeds in herbaceous perennial plots than wood chips. Similarly, sawdust made a better mulch for Christmas tree production in terms of weed control, microbial biomass, and soil chemistry. Another comparative study found rubber to be less effective than straw or fiber mulch in establishing turfgrasses.”

          In regard to the permanence of rubber mulch she says, “Far from being permanent, rubber is broken down by microbes like any other organic product....Although some of the additives used in tire manufacture are toxic to rubber-degrading bacteria, there are white-rot and brown-rot fungal species that can detoxify these additives. While isolating these microbes has been beneficial in developing natural mechanisms to recycle rubber products, it also points out the fallacy of assuming that rubber mulch is “permanent”. Furthermore, it alerts us to the very real possibility that car tires leach toxic compounds into the landscape.”

          If we listen to the producers, marketers, and advertising it would appear that rubber mulch is an environmentally friendly solution to a major waste disposal problem. However, Dr. Chalker-Scott concludes:

          “• Rubber mulch is not as effective as other organic mulch choices in controlling weeds

          • Rubber mulch is highly flammable and difficult to extinguish once it is burning

          • Rubber mulch is not permanent; like other organic substances, it decomposes

          • Rubber mulch is not non-toxic; it contains a number of metal and organic contaminants with known environmental and/or human health effects.”

          Before using rubber mulch please read Dr. Chalker-Scott ’s article!!!!

Copyright 2008




          A reader asked, “Is it too late for a fall application of fertilizer? If not, what should I reach for?” The fall or winterizer fertilizer goes on sometime between Halloween and Thanksgiving. Put on the winterizer fertilizer the weekend after you do your last mowing and you put your mower to bed for the winter. Some companies call it “winterizer” and some “fall fertilizer”. Usually an application of regular fertilizer is put on about Labor Day and the winterizer fertilizer is the last application for the season. If you only fertilize twice a year, these two applications are the most important. If you have already applied one application of fall fertilizer and we have a long fall you may want to put on another application when you put your mower away for the winter as the nitrogen in the first application will be used up and not available for the winter.
          Remember that now, after the first light frost, is also a very good time to go after the broadleaf weeds like dandelion, henbit, ground ivy, and clover. Apply Trimec (Earl May Lawn Weed Killer, Weed-Be-Gone II), Super Trimec (Earl May Super Brush Killer), Ferti-lome Weed Free Zone, re Clopyralid, or Triclopyr. You will usually need to put on 2 to 3 applications, 7 to 10 days apart to really kill these weeds, or at least weaken them so they do not survive the winter. The products listed will not kill your grass when applied according to label instructions. Make sure you read the label and the list of active ingredients to see what the weed killer contains. Remember, do not use Glysophate (Kleen-up, Round-up) as this will kill your grass as well as the weeds. Always use at the rate recommended by the manufacturer as more is not better and may injure your lawn. Most of the weeds listed have a waxy surface so a “Sticker-Spreader” ( Earl May Turbo , Acme Sticker-Spreader) helps the product stick to the leaf and improves the effectiveness.

          I like Super Trimec (Earl May Super Brush Killer) as this can be applied when the temperature is at least 45 degrees F. when applied. Trimec (Earl May Lawn Weed Killer or Weed-Be-Gone II) and glysophate (Kleen-up, Round-up) have to have the temperature at least 55-60 degrees F. or above to be effective.

Copyright 2008