Winter protection for Japanese maple
I lost a Japanese maple last year and a nursery told me it was due to the polar vortex. I planted a new lace leafed red Japanese maple this year. How should I protect it this winter? Thanks, Joe
Jackson County Michigan
Japanese maples much north of Jackson survived the extreme temperatures we had this winter. In fact 6 or 7 years ago we had a colder winter that lasted much longer. We normally do not protect Japanese maples in the winter. Japanese maples are rated for Zone 5 which fits Jackson's climate. This past winter the coldest record temperature at the MSU Enviroweather station in Leslie was -15 on Jan 30 and -17 on Jan 31. These temperatures fall within the -10 to -20 range for zone 5. Likely a bigger problem is that once we got past the cold of January the winter was not that cold. By March 10 we hit 45 and it rose to 63 on March 14. Temperatures stayed warm hitting 66 by March 28. Plants began to come out of dormancy and a few days later temperatures were down to 18 degrees. This is where buds get damaged when plants come out of dormancy too soon only to get nailed by temperatures 14 degrees below the freezing mark. The same thing happened in 2012 with Japanese maples became active early only to be damaged during a cold spell. A second problem this spring was the continuous rainfall amounting almost 19 inches by June 20 when we normally get 11 inches. Japanese maples do not tolerate poor draining soils and when heavy rainfall occurs in slow draining soils we can get serious root damage. Two problems of quick fluctuations in temperature in spring and heavy rainfall both combine to damage Japanese maples. I think at this point focus on use of mulch about 2 inches spread evenly under a maple to help protect roots from loss of moisture and quick changes in temperature. Do not let this plant become stressed during dry periods in the summer.