April 3, 2014

Steve Scheuring, Account Manager, Horticulturalist Expert of Twin Oaks Landscape has this to say about what we can expect this spring….

This has been a very long and hard winter for most of us.  I am ready for spring!  Here are some landscape items to consider for this spring.

  1. Pest & Disease:
    1. The snow cover has made it difficult for animals such as rabbits and deer to find food.  I have seen a lot of bark missing on stems and trunks.  If a ring has been removed from a trunk or stem, it will usually bud out in the spring and go into decline once all of its residual energy has been used up.  Most likely, it will be dead by late spring or summer but it may take a full year.Vole Damage
    2. Expect lots of vole trails through the lawns (SEE RIGHT PHOTO).
    3. The extreme cold may have killed many insect larvae that harbored above the snow line.  If so, there may be limited borer or other insect damage this summer.  We still need to keep a watchful eye.
    4. Snow mold on turf areas may be extreme this year.  Once the snow melts and the grass begins to grow, effected areas will be evident.  Aeration and over-seeding is the best solution.
    5. Landscape plants:
      1. In our area, which is zone 6a, we observed temperatures blow hardiness zone designations.  It reached minimums of -14 and -21 degrees, respectively, which are colder than the hardiness zone minimum of -10 degrees.  One highly unusual meteorological aspect of the cold wave was the presence of strong winds during much of the event; most extreme low minimum temperatures take place under relatively clear, calm conditions.  Such windy conditions act to  increase convective heat loss from the plant tissue, potentially increasing the likelihood of plant injury.
      2. Never less, there are several reasons for optimism even in areas where temperatures dropped below hardiness zone minimums.  First, many plants we commonly utilize for landscaping are hardy to a zone colder than our location.  So in Southeast Michigan, many conifers and other common trees will likely be affected.
      3. Second, most landscape plants should have been at or near their maximum cold hardiness since we have had a steady dose of cold weather most of the winter.  Plants will gain or lose cold hardiness as weather warms or cools during the winter.  When the weather turns cold and stays cold, plants typically achieve their greatest cold hardiness in January and early February.  Our most common scenario for widespread cold damage is when severe cold is preceded by an extended warm-up.
      4. Lastly, the extreme cold was preceded by significant snowfall, providing an insulating layer of snow that should have protected herbaceous perennials and low lying shrubs.
      5. Predicting freezing damage is difficult due to the variety of factors that come into play, such as degree of plant hardiness, severity and duration of cold, conditions preceding the severe cold etc.  Winter isn’t over yet.  Most damage from the “Polar Vortex” cold outbreak won’t be apparent until spring.  Michigan State University Extension advises to watch for symptoms including branch die-back, failure to break bud, and even plant death.  In some cases, landscapers or homeowners may observe a “snow-line,” indicating the depth of snow at the time of the severe cold.  Above the line plants may be damaged; below the line they are alive and healthy.  The plants that are most likely to be damaged are those that are marginally hardy for a given zone.  Some common plants I expect possible damage are Rhododendrons, Golden Vicary Privet, and Holly.  Plants such as Boxwood and Yews that have been pruned, not sheared, at the proper times will have less or no damage.
      6. Assessing and correcting winter damage to trees and shrubs will be a key component of spring activities for many homeowners and landscapers.