Sleetpocolypse ’21
I felt like a headline would provide more description and context than I can writing prose. But we’ve just been through the worst freezing rain event since the early 1980’s. Thats a long time and you need to put that in to context when thinking about the damage in your garden. Luckily, this storm came late in the season for us which did two important things, it limited both the longevity and intensity of cold. The lowest reading at PDX and also my home in north Portland was just 24ºF. Relatively mild. Unfortunately, the worst kind of weather for a garden can occur not lower than that but warmer. The intense ice accretion that occurred in the northern Willamette Valley occurred where temps didn’t drop below 29ºF. Freezing rain does its most dirty work above that temperature and closer to freezing.
Three waves of freezing rain
Anything over .25″ of ice is considered major.- that adds 30 times the weight to branches (roughly). Our ice came in three waves in the metro area. The first wave was mostly snow and sleet in the city but south of town the subfreezing air was shallow but spread as far south as Albany. There- complete glazing caused immense damage. Some areas locally accumulated 2″ of ice during this phase. This caused catastrophic damage to the states hazelnut industry and all woody plants in the central Willamette Valley. During this time the precipitation was sleet and snow in Portland and nearer the gorge. The second round of freezing rain came a day later with snow changing to sleet and then freezing rain over a wider area- but less intense over the south. The final wave of freezing rain impacted the city and hills primarily with an additional 1.0″ of ice. This final wave concluded on the morning of February 15th. In all my north Portland garden recorded 10.25″ of snow/sleet and 1.25″ of ice. That exceeds the largest storm since at least 1996. That storm (The Boxing Day Storm) had more ice but was restricted to the Portland basin. In my 40 years of gardening in Oregon , this is about as bad as an ice storm gets. I anticipated a lot of damage and that has come to pass.(A close runner up is the Dec.21-24 snowstorm/ice storm in 2008, 14″ snow 1/3″ inch of ice) Much less tree damage.
You are probably wondering what to do. OK.
First things first. DURING a freezing rain event/ice storm do NOT try to remove ice off of frozen plants. You will only do damage and possibly endanger yourself. As garden writer Henry Mitchell wrote- “Sleet- nothing to be done, shut the shades.” Its very tempting to free your plants but more than once a branch has come clean off by being shaken. RESIST- this is for future reference. Removing snow is great but ice-leave it up to nature.
Rocked plants:
These are shrubs and trees that have listed (rocked) from ice weight. First analyze the amount of list and if it can be straightened by hand or do you need to use a wInch? Be very careful not to further damage roots. Even relatively large trees can be righted and if you pack the roots on the weak side and plop a large rock or cinderblock on that side of the rootball you have at least a 50% chance of the tree growing on normally. Watch the tree closely through summer. Definitely stake it for more stability. And water it well if it needs it. Roots may have been torn and it will take time and water and good care to repair them. The same can be true for large shrubs, Treated this way they may be righted and staked to achieve a strong root system again. Also, shading the torn root side (with a boulder or cinderblock) aides in root growth on that side of the plant by retaining moisture. If the plant still seems top heavy you may prudently cut off foliage until the plant is more balanced.
Broken plants
This is a lot more complicated and it depends on your own ability to deal with the damage. If it seems like more than you can handle PLEASE call a professional. They will likely ease your mind and are willing to take on complex pruning. Don’t be afraid to ask.
Check out the kind of damage. If it is a clean snap but with jagged edges, you might make a clean cut on the plant. Ideally, the cut should be angled so that the wound will not collect water. And that is seldom the case but its what you are going for. For damage that is a tear, or the branch was ripped downward leaving a scar taking bark with it I will generally clean up the cut so that nothing jagged is left but these wounds must heal themselves. They definitely will too over time- it might look AWFUL but this is where nature often has your back. Nothing should be painted over the wound- oxygen will cause the healing that is required.
During spring clean up and storm clean up I actually sterilize my pruners. 1 tsp bleach to a gallon of water. Prudent if you are pruning more than one thing to diminish the chances of swapping pathogens. Just give them a dip between species.
If a tree has had MAJOR losses- I’ve seen some poor Japanese maples that just literally exploded I have good news. They will mostly heal themselves. It may take a year or 5 but they will regain form. This of course is if the losses to the tree are not catastrophic. This is where I implore patience. Let nature repair itself. Often a year or two after a severe storm the wounds are barely discernible. I say this with years of experience. At the same time if you have to call death on something, this is when I wouldn’t hesitate to replace the plant with the same thing regarding small trees and shrubs.
So, spring cleaning has come early and nature made a big old mess. I’ll reserve my opinion on the performance of certain trees for another post.
As of now NOAA is calling for slightly below normal temperatures for March with normal precipitation. It is simply getting too late in the year for arctic air to makes a reliable path to us. Its happened in the past but after Valentines Day the possibility dives by half and then less and less likely as the days go on.
Happy Spring.
Can’t wait to see you at the shop.
two additions:
Italian Cypress and Arborvitae suffered horribly in this storm. Cypress have become disheveled and arborvitae are bent and flailing. My best advice is to wait at least a month before you do anything. You’d be surprised at the amount of recovery with in that time. If you don’t believe me take a picture of the storm damaged plant and then wait one month. Improvement happens even if its incremental. So, after that point if you decide to prune remember that Cypress can be quite severely shorn and they will even tolerated topping- a new terminal leader (s) will form. Again, wait at least one month- thats usually the length of time they need to outgrow their ice hairdo.
Arborvitae are a bit different. They will not tolerate shearing. Its best to clip errant branches off one at a time. I recommend staking bent arborvitae before pruning them. It takes some work but bamboo and zip ties can work wonders. If it is too tall or a goner then you can do heavier pruning. Just don’t expect a lot of regrowth.