2012/2013 Winter

In this Newsletter…

– Winter damage on your trees
– Buckthorn eradication in winter
– Bur Oak Blight in the Twin Cities
– Emerald Ash Borer (EAB) update
– U of M Plant Disease Clinic

Winter– Damage caused by our harsh Minnesota winters is fairly common in landscape plants.  Winter sun, winds, temperatures, heavy snow or ice, and browsing animals can damage trees severely and even lead to death in extreme cases.  Extreme temperatures and wind are particularly damaging to conifers, as the plants lose moisture through their needles that cannot be replaced when the soil is frozen.  Unfortunately needles that have become desiccated (dried out) over the winter cannot recover.  Therefore prevention is necessary for susceptible conifers, particularly those planted in areas exposed to windy conditions.  Young trees, particularly maples, with thin bark are also prone to sun scald, caused by bright winter sunshine.  This is the reason many young trees are recommended to be wrapped in dormancy.  Additionally, the scarcity of food over winter months can also cause deer, mice, and rabbits to feed on susceptible landscape plants including many shrubs and fruit trees.

Buckthorn Control- Buckthorn is an invasive species that causes many problems in Twin Cities’ landscapes.  The aggressive growth of buckthorn crowds out many native plants in woodlands, and threatens the natural regeneration of our Minnesota forests.  Control of buckthorn, as anyone who has worked with it knows, can be difficult.  Fall is frequently considered the time where control measures are most effective against buckthorn, however we have also developed very successful treatments that can be done over the winter that have many advantages.  Winter applications can be done without any damage to other plant material.  The buckthorn can be killed chemically without associated removal costs.  This manner of control allows native plants to regenerate, while maintaining visual screening, as well as providing food and habitat for wildlife.  Buckthorn control is tricky and each property requires a different strategy for control.  This is another tool in our repertoire to provide you with as many options as possible to restore our native vegetation.

Bur Oak Blight (BOB) – There are still many unknowns regarding this leaf blight disease, identified in Iowa in the mid 1990’s and confirmed to be in the Twin Cities.  According to the U of MN Yard and Garden News, the disease affects bur oaks under certain specific conditions, and can lead to branch death and tree mortality in some cases.  It is worthwhile to look for the disease in the winter as a common symptom is holding on to dead brown leaves throughout dormancy.  If you have a bur oak with brown leaves still attached through the winter, call us, it is very beneficial to diagnose the disease before the loss of major branches.  Premium Tree Protection, with the University of Minnesota’s plant pathology lab has identified trees in the Twin Cities metro area that are suffering from BOB.  The pathology lab can now use DNA testing for the disease, even in the winter.  Fortunately, a treatment has been developed that is showing success in combating bur oak blight.

Emerald Ash Borer (EAB) update– Found in Minnesota in the spring of 2009, this exotic insect threatens Minnesota’s ash trees on public and private property.  Due to the severity of the risk posed by EAB, intensive surveys have been conducted in the Twin Cities.  Fortunately, the insect has been found in a fairly confined area near the border of Hennepin and Ramsey counties.  In the fall of 2012, emerald ash borer was found in ash trees in Fort Snelling Golf Course, within ½ mile of Dakota County.  A great deal of research has gone into EAB since its initial discovery, including innovative treatment techniques involving the introduction of stingless wasps that feed on the insects’ eggs and training dogs to detect the presence of infested wood.  Premium Tree Protection is hired to protect hundreds of ash trees throughout the metro area, and we have developed a treatment protocol using the latest research and methods. We feel so strongly about the success of our treatments that we can offer a money back guarantee.  The Minnesota Department of Agriculture maintains an excellent web page for information on EAB.

Plant Disease Clinic – As exclusive specialists in plant health care, we can frequently diagnose disease and insect damage during a visual landscape inspection.  Some diseases can be difficult to diagnose such as Bur Oak Blight, Oak Wilt and Dutch elm disease.  When we cannot diagnose a disease on site, or if diagnostic proof is required, we can take samples to be analyzed at the U of MN plant disease clinic.  We are fortunate to have a pathology lab in the Twin Cities, and they can now perform molecular diagnostics (DNA and RNA based assays) for difficult diagnosis like Bur Oak Blight and Oak Wilt.  Soil samples can also be analyzed at the University of Minnesota to customize fertilization and address any deficiencies that may be present in your soil.  Rest assured that if our experience cannot diagnose your tree issues immediately, we have resources in place to get an accurate diagnosis with a little time and effort.