Trees and shrubs are certainly affected by the weather and show signs of stress and decline that we don’t always associate as being related to it.
One reason we overlook weather’s role is that as homeowners we can take too short of a time frame into consideration in our evaluation. Consider the cumulative effects of the weather over several growing seasons to gain a better understanding of the decline of a tree or shrub in the landscape.
Richard Hentschel, a University of Illinois Extension Educator in Horticulture, recently explained the importance of taking this long-term overview. “The drought of 2012 is an appropriate place to start an analysis of how weather has affected our landscape plants this season. That was a year which began with adequate moisture but then weeks without rain set in. Unless homeowners provided deep watering on a regular basis during that time, trees and shrubs undoubtedly lost root mass. It’s not at all unreasonable to assume that a 20-foot root on a tree could have died back to 15 feet in length that year.”
Hentschel’s explanation of a multi-season stress evaluation continued, “The 2013 growing season saw an average amount of moisture overall and plantings likely experienced some degree of recovery from the drought.
“However, a full recovery of the root system on a large tree in that one season would be doubtful with a drought as severe as that of 2012.”
Next came the brutal winter of 2013 with extremely low temperatures for long stretches and strong drying winds, which were stressful to healthy and recovering woody plantings. The current punch to our landscapes has been the above average amount of rain in 2014. Tree and plant roots sitting in excessively wet soil cannot get the oxygen they need to live and begin to die off.
As roots die, soil borne fungi can invade, quickening the tree or shrub’s decline. This year many homeowners have experienced landscape losses due to root rot and crown (at the soil line) rot. Above ground losses have included many needle blights and casts on needled evergreens and canopy losses on large shade trees.
Understanding weather’s multi-year effect on your landscape plantings is an important start in the evaluation of plant decline. Contact the Helpline for assistance in this.
Email your home garden and lawn questions to email@example.com or phone the Master Gardener Helpline at 630-955-1123. Visit our website at http://web.extension.illinois.edu/dkk/.
Julie Moore has been a Master Gardener volunteer with the University of Illinois Extension in DuPage County for 10 years and has a degree in Ornamental Horticulture from the University of Illinois.Tags: Gardening, weather