A Rude Awakening

February 11, 2014 (18)Our winter, which shows not one sign of abating, has been our snowiest and coldest for 20 years.  My landscape has rarely been subject to temperatures below zero – never the extreme below zero numbers that have been routine this winter.  A worst case winter like this is bound to have consequences.  I fear the spring may not only be an awakening, but could well be a rude awakening.  Have I planted marginally hardy species in my garden?  Yes.  Magnolias and dogwoods are somewhat marginal here.  Other trees common to my area, as in redbuds, London Plane trees, sweet gums (liquidambar), and even tulip trees are very sensitive to extreme cold.  Many specialty evergreens that thrive in the Pacific northwest that have been planted in my zone may not fare so well.  I have already seen many Alberta spruce with substantial cold burn. I know of several long established sweet gums who routinely have crown dieback in a middling cold winter. What will happen to them this year?  Furthermore, years of reasonable winter temperatures have encouraged me to try plants that are on the edge of my hardiness zone.  This has worked for many years.  This year, I may be in for a little course correction.

snowy landscapeI am not a worst case alarmist. It could entirely be that I will see little damage.  But professional growers I have known for years are concerned about what our spring will bring.   I have magnolias which are definitely a zone 5, and maybe a zone 6. For 18 years, those trees have done better than survive.  But weather cycles are much longer than my gardening lifetime, and the lifetime so far of my landscape.  I am quite sure there is not a single plant in my yard which is 100 years old or better.  Bob Schutski, professor of horticulture at Michigan State and well known lecturer in landscape practices, predicts we will have no magnolia flowers this spring.  Ouch.  I hear of peach growers in Michigan talking about total crop loss.  My gardening friend Michael whose barn is pictures above-his mountains of snow may be the least of his worries.  He has trees and mature shrubs missing their bark above the snow line.

mature quinceThis picture from his garden is from a mature quince.  Every branch which above his current snow line has no bark.  The 6 feet of snow we have had so far this winter means that there is little winter food for wildlife.  This damage is most certainly the result of gnawing from hungry rabbits.  Though the extreme cold will take its toll, the deep snow meant the bark of this quince would become rabbit food. A shrub or tree stripped of its bark can no longer sustain the life of that limb.

girdled treeThe damage to the landscape may not be apparent until the snow has melted, revealing disaster like what is pictured above.  Deep snow means wildlife are struggling to find food.   Deep snow can be damaging in other ways.  When the sun moves higher in the sky, the light reflecting off of the snow can thaw evergreen branches.  An evergreen branch brought out of dormancy by the reflected light and heat of the winter sun can burn, or die, once temperatures drop dramatically at night.  Tree bark that warms during a sunny day, and then refreezes at a rapid rate may produce sunscald.  Most frequent on the south side of a tree, sun scald can kill the inner bark.  Winter burn, sun scald, frost cracks-these are all conditions brought on by an extraordinary confluence of  extreme cold, extreme snow and sun. Rabbit damage copy.previewFrost cracks, or vertical splits in tree bark from extremely low temperatures, can damage a tree.  These splits, though they may heal, are an ideal point of entry for disease and insects. No gardener has any control over any of this.  A friend in Chicago has written that she sees frost cracks on London Plane trees now.  Circumstances beyond one’s control are never easy to take, but some understanding can help relieve the shock.  I have been thinking when spring comes, all will be well in my world.  In fact, five weeks hence, I may have issues in my landscape that are not to my liking.

OLYMPUS DIGITAL CAMERAAt least I have no deer.  My very populated urban area is not a habitat of choice.  Were I to walk to my rose garden once the snow had melted, the sight of my arborvitae denuded by hungry deer might make me black out. This gardener whose plants are pictured above-I cannot imagine their anguish.  I have had severe damage to my arborvitaes from ice and wind that weighed down and splayed out long branches.  Though they have all been professionally staked by an arborist, they have not completely grown out of the damage which dates back six years.

winter light 4Our winter is not even close to a close.  Am I beat down to the ground by the incredibly cold temperatures and relentless snow-yes.  So far today we have had high winds, hail, and freezing rain.  Though there is nothing I could have done to protect my plants from exposure to any of this, as usual, I have hope.


Say It Ain’t Snow

more-snow.jpgIn Detroit, 49.3 inches of snow have fallen so far this winter, more than the full season average of 42.7 inches, and there are at least two months left in winter.  Detroit is seeing its snowiest January on record: Detroit has received 31.3 inches so far this month, breaking the old record of 29.6 inches set in January of 1978, according to the weather service’s White Lake Township station. And more snow is on the way.  There are those who might think this is a record of dubious merit.  But though I am truly tired of the endless snow, I am also much relieved.

DSC_7500The shop is about 30 miles north of downtown Detroit.  The USDA plant hardiness map puts us in Zone 6a.  This means that plant which are hardy from -10 degrees below zero to -5 degrees below zero should live and prosper here.  True plant hardiness is not all that formulaic.  There are invariably mitigating circumstances.  Some years those circumstances work for me.  Other years, marginally hardy plants slip away.  Some zone 7 plants will live for me, provided they are planted in very sheltered spots, and have good drainage.  But no matter my efforts, the proof is in the winter putting.

Jan 26 2014 (3)I have clients that have old Franklinia trees, 2 story tall American hollies, Brown Bracken magnolias- and other more southerly specific landscape plants that are healthy and robust, in spite of our plant hardiness zone designation.  I am sure that proper siting played a big part in their survival.  I have another client who lives in Detroit, and with much effort, mulching and wrapping, overwinters certain palms in the ground.  Palms-really?  Detroit is a big city with lots of buildings.  The mass of all of those buildings holds the heat, and the height of the buildings protects plants from wind.  Plants are very specific about what they want, and what they will tolerate.  The hardiness borders are not fixed.

Jan 26 2014 (8)There is no reason not to push the envelope, if there is a plant you feel you cannot do without.  The -10 degrees to -5 degrees is a worst case scenario in zone 6a.  So what gardener doesn’t like to plant dangerously? That is part of the fun of having a garden-stretching the limits.  But we have had temperatures that are coming close to that worst case scenario, and colder temperatures yet to come.  What does this mean for the garden?

Jan 26 2014 (22)First up, I need to refer back to the snow cover, as amply illustrated above.  Snow is water that freezes as it falls.  As this granular and crystalline form of water piles up, it forms a blanket which, despite its cold composition, has great insulating properties.  Think of all of this frozen water, with air trapped in between each crystal.   Years ago I was so surprised to learn that spring flowering bulbs never freeze solid.  The earth has a latent heat which keeps most bulbs just at or above freezing.  Bulbs that I plant in pots for the winter, that freeze solid through and through for lack of sufficient protection, will rot come spring.  Insulation is an important part of weathering the winter.

Jan 26 2014 (31)Where am I going with all of this?  The insulating role of soil, and in our present case, heavy snow, plays a major role in protecting landscape plants from cold injury.  My landscape plants began slowing down in August.  In an ideal season, the transition from the growing phase to the sleeping phase is very long, and imperceptibly gradual.  Sudden and extreme cold, like what we experienced several springs ago, will catch a plant off guard.  A plant which has begun leafing out has had a biological, final, and emphatic call to leaf out.  The new shoot that is out there is vulnerable to an abrupt change in conditions.   If the environment suddenly goes cold, the new leaves will suffer.  If the dramatic cold is cold enough, and long enough, branches of trees can die back.  In our cold a few springs ago, many Japanese maples died outright.

DSC_7503Tulips are well prepared for nature’s mood swings.  The leaves poke out of the ground-they test the early spring waters. Unforeseen cold weather can disfigure the leaves, but the buds stay tucked away underground until the weather reliably warms.  An unexpected freeze when the tulips are in bud-I shower them with water. The water will freeze before the blooms.  Gardeners, and spring blooming plants-they are endowed with incredible fortitude.   My trees and shrubs have been dormant a long time.  The roots of my magnolias are deep in the soil, and mulched with 40 inches of snow.  I am thinking – and hoping – that they will survive this brutal cold without incident.

Jan 26 2014 (27)If I have to have the cold, then I want as much snow as possible.  Middling cold winters with no snow cover worry me.  Though I know the will to live is incredibly strong, will is not everything.  Middling cold can damage or kill plants that have no insulation from snow.  As utterly bored and irritated as I am by the extreme cold and the relentless snow,  I am in the gardening gig for the long run.  That would mean a spring in which I see all of my plants leafing out, ready to grow.  So bring on that snow.

Jan 26 2014 (24)Underneath our 49 inches, a garden.

Snow Day And Night

parrotia-in-January.jpgThe  pictures recovered from my iphone of the rose garden in June a few days ago were indeed a pleasant interlude.  However, the winter season is all over my garden.  Buck says we have 10-12 inches already on the ground, and our heaviest snowfall is yet to come.  Overnight, another 6 inches.  I have not one problem in the world with that.  Due to arrive shortly-zero and below temperatures.  I told Buck it was at least 20 years ago that I remember temperatures this cold.  Given an extremely low air temperature, I am glad that all of my plants have roots buried in the ground.  With the temperature set to drop to zero, I am further comforted by the insulation provided by all of this snow.

parrotia-in-winter.jpgWinter hardiness is an exact science, provided you factor in each and every one of the mitigating circumstances. OK, it is an inexact science. Plants reputedly hardy in my zone that are planted in poorly draining clay soil die out regularly.  Perennials and shrubs planted so late in the season that there is no time for any rooting to take place can be heaved out of the ground in a freeze/thaw/freeze period.  Marginally hardy plants placed in protected locations, and mulched for the winter stand a better chance of survival.

buried-stairs.jpgPlants have an extraordinary will to live.  They will suffer my careless planting and indifferent siting, my over watering, my thoughtless pruning and wrong headed culture without so much as a peep.  But once the insults reach a critical mass, a plant will die.  My garden starting slowing down this past August, and we have had fairly cold and snowy weather since November.  The garden couldn’t be more ready for the cold. I doubt that anything in my garden will be damaged by the brief but extreme cold to come. Dormant is dormant. The insulation that will result from all of this snow is a bonus.

Heavy snow does not keep any plant warmer.  The snow is an insulator.  It protects against any response to a rapid change in conditions.  With mulching, or insulation from snow, a plant that is frozen will most likely stay frozen until the time is right to grow.  Our temperature today was 29 degrees.  It has dropped precipitously to 9 degrees.  It is forecast to drop again to zero on Tuesday.  Once a plant has gone dormant, it is the hope that the dormancy will be maintained.  Up and down, freeze and thaw-big changes are not good changes.  If I have a mind to mulch a tender perennial for the winter, I do not apply the mulch until the ground is frozen.  The mulch will help frozen ground stay that way.

snow-day.jpgI dress in lots of layers in weather like this.  A turtle neck, a fleece jacket, a down vest and a down coat keeps me comfortable outside in cold weather.  Warm air is trapped by all of the layers.  My sheepskin winter boots, warmed by the radiator, will stay warm for several hours outdoors-the sheepskin holds the heat.  I am not looking for my winter gear to warm me up.  I only ask that it help me maintain a comfortable temperature outdoors.

heavy-snow.jpgI have been in and out all day today with my camera.  A snowfall of this magnitude is not an every day garden event.  Piling on the clothes prior to a garden visit is an event the corgis notice.  They know something is about to happen.  I have had them outside on and off all day today.  Though they are not equipped to handle really deep snow, they have been game.  Milo plows, and Howard follows in his tracks.

yew-topiary.jpgAt 7pm it was snowing even harder.  The snow had gotten more powdery, and the wind was blowing it around.

winter-storm.jpgThe light strings in the pots were unfazed by all the snow.  All else was a deep blue gray.

winter-pots.jpg)My winter pots-pretty fazed.  This is a moment when I am glad that we take such trouble to insure that the winter arrangements are secure.  The centerpieces go deep into the soil in the pots.  As that soil is frozen solid, it would take a lot to dislodge them.  The eucalyptus is preserved, and will bend before it breaks.

Buck.jpgBuck is not a whatever the weather guy, but even he was intrigued.

winter-pot.jpgsnow clogged winter pot

snow-bound.jpgburied boxwood

Milo.jpgMilo, unfazed.