Hopefully the extreme lows we’ve experienced are killing off some of our insects and pests that have taken hold the last few years. In particular, the Emerald Ash Borer, the marmorated stink bug, and the Asian tiger mosquito. For the EAB, larvae experience death at different levels of extremes. 34 percent of EAB larvae die if the temperature hits 10 below zero, 79 percent die at 20 below zero.
We were somewhere in between that range; if those statistics hold true then January’s weather extremes potentially took out about 50 percent of the larvae. The EAB is considered to be the worst forest problem of our lifetime; comparable to the blight that took out chestnut trees across the U.S. in the early 1900s.
The marmorated stink bug and the Asian tiger mosquito are probably not going to be as affected by the cold, although there may be some reduction in their numbers. I’d suffer through a month of polar vortex if I knew it would take out the mosquitoes, but unfortunately they are hardy little souls.
One other “good” cold weather benefit is the effect it has on Lake Erie. Ice on the lake reduces evaporation, and may help raise lake levels. Also, temperature greatly influences water chemistry. Our lake, river, and stream water qualities improve when the temperature plunges.
The biggest problem will be the potential injury to plants. Most won’t be harmed, as they hardened off in November and went into dormancy. Unfortunately, plants that bear fruit look to be the most affected. Peach trees in particular are sensitive to the extreme cold, which breaks my heart. I love our local peaches.
Other plants such as evergreens and boxwood shrubs may have a few more brown leaves than usual but should be fine. Shrub roses were probably not affected, but hybrid tea roses are more sensitive and may have damage if they weren’t overwintered properly. Michigan State University Extension advises us to watch for symptoms such as branch die-back, failure to break bud, and even plant death.
In some cases, landscapers or homeowners may observe a “snow-line” on their plants, indicating the depth of snow at the time of the severe cold. Above the line, plants may be damaged; below the line, the plant will be alive and healthy. In essence, you could potentially wind up with a two-tone plant; half dead and half alive. Depending on the size and shape, you may be able to prune off the dead sections and still have a plant left that looks normal.
Other issues to monitor include damage from salt and chemicals. If you have shrubs and plants growing close to the road that are constantly being exposed to road slush, you will notice a lot of browning and plant death this spring. Anyone who has tried to get salt out of a shaker during our humid summers knows that salt readily absorbs water. Every time you bring your car off the street and onto your driveway, salty ice will eventually melt off the car and run into your grass as well.
We may feel aggravated right now with Mother Nature, but the repercussions of this weather will be felt and seen for many weeks to come.