Cold killed Oak leaves

[Magicman]

I just noticed the leaves on my White Oak tree today.


 
They were visibly drooping. 


 
So then I took a close look at my Cherrybark Red Oak.  Yup, all drooped.


 
I broke off a small limb and confirmed that all of the leaves are dead.  We had 27° last week which killed all of the leaves on all of the Oak trees.  The leaves are also dead on all of the ornamental plants.

I suppose that the trees/plants will bud out again, but I also suspect that they are severely stressed.

[stavebuyer]

About 15 years back we had what we called "the black spring". A hard freeze in mid May after all the trees were almost fully leafed out. The hills turned black as the leaves wilted and later dropped. The trees all eventually sprouted new leaves and I don't recall any long term damage. 

The fruit tree blossoms usually get hit every year here but fully developed leaves is a rarity.

[SwampDonkey]

My white oak gets hit once in a while in June, not usually totally dead, but injured. Ash trees, fir and white spruce are most susceptible up this way, will kill the new shoot and leaves. Maples and aspens seem to be tougher. I've seen them white with frost and not die, burnt on the edges.

[Don P]

That freeze stavebuyer mentioned hit the Christmas trees here hard.

[bitternut]

I have seen the same thing happen in my woods a couple of times to ash trees and and once to the oaks. They all recovered fine and put out a new set of leaves. It all
depends on if the new leaves have been out long enough to harden off when the freeze hits. Pretty scary to see all those black leaves.

Never seemed to have any lasting effect on the trees. Probably not good to have a drought or gypsy moth infestation following the freeze. I think there will be a full recovery.

[bluthum]

Basic rule of thumb is hardwoods can stand 1 leaf freezing event but 2 in the same season may be fatal. Softwoods usually die with 1 leaf freezing event. Of course rules of thumb are not carved in stone.

I've seen some drastic hardwood leaf freeze offs but it never seemed to matter to the trees health long term beyond usually eliminating that years flowers.

[SwampDonkey]

The good thing about spruce, fir and jack pine is they have advantageous buds or inter-whorl buds. If the new shoot is killed one of those buds produce a shoot to continue onward. I often find some shoot injured fir and spruce, especially on lower elevations. They carry on. Red spruce and black spruce here are later trees to emerge, not until mid June, not likely to be hit by frost. White spruce and balsam fir are elongating in late May. We can get killing frost until almost June 15.

[Magicman]

White Oak acorns are a "one year" event so there may be none this year.  Red Oak acorns are a "two year" event so we shall see.

I am curious about the Azaleas and other Ornamentals.  They keep their leaves through the Winter, even through freezing weather, but all of their leaves are dead.  Must have had something to do with the Spring sap flow?? 

[SwampDonkey]

I'm not up on the science, it's been years and science evolves. It may have something to do with dormant daughter cells in the cambium that 'woke' and got nipped. We had a fir tree struck my lightening, every bud was killed. No single shoot emerged in 2 years, I cut it down. The old needles were still green, but you have 3 or 4 years and they die. You kill a certain cell off and the tree is done for.

[RetiredTech]

We had 27° last week which killed all of the leaves on all of the Oak trees

  I haven't noticed the oak trees with dead leaves, but it killed the leaves on all the fig trees on the property and got about half my lemon tree that is planted on the south side of my generator shed.

[Magicman]

Looks like our this year's Blueberry crop took a severe hit. 

[Don P]

The mockernut in the front yard was just at fat bud, no leaves yet, the fine twiggery is black. Were the blueberries running early for there?

[Magicman]

Probably because we did not have much Winter.  It did not drop below freezing but a couple of times. 

I am going to take a much closer look at the Blueberry Bushes today.  When I was looking earlier in the week I had not realized what had happened to the Oaks.

[RetiredTech]

  My blueberry's are just beginning to put out. I think their OK. The plum tree had already bloomed but still had blooms on it. I'm hoping it will make fruit.  

Edit: I noticed today the Mulberry trees leaves are dead too.

[SwampDonkey]

Last two years my wild plums were covered in blossoms, not a plum to be had. But last year was one year the grapes escaped the frost. It was cold and wet until the middle of June, no bees much. Never actually saw a honey bee until late August, in the yard maple, again.

[Magicman]

I do not believe that we know the extent of the kill-off yet.  In am breaking dead branches off of trees and shrubbery and cut down a dead Red Maple yesterday.  The lawn and drive are continually being covered with falling dead new leaves. 

It's not that it got that extremely cold (~27°), but the plants were pumped full of Spring sap flow and froze.

[RetiredTech]

   Fig trees still haven't put on new leaves. I'm a little worried about them. Most of the blueberries are OK. We had a few early bushes that already had small berries on them that got bit pretty bad, but they still seem to be alive. The others are putting on berries now. The small wild mulberry near my house has put on new leaves. The satsumas and lemon trees got bit pretty hard. I lost about half of my lemon tree. I gave up on satsumas. They're always the first to go in freezing weather.

[Magicman]

I am sure that most of the kill will right itself, but it's strange and something that I have never witnessed before.


 
Cherrybark Oak is gradually adding new leaves and the dead ones are gradually falling.  The Beech seen on the left is OK, and the Live Oak on the right has top damage.


 
A lower limb of another Cherrybark Oak.  So far it has made no attempt to add new leaves, not even on the upper limbs partially seen in the upper picture. 

The Water Oaks seen in the background are all OK.


 
The top half of this Live Oak lost most of it's leaves.  It should not have lost any.


 
This ornamental should not have had any kill nor leaf damage.  So far it is doing nothing.

It seems that Post Oak took the hardest hit, and the Beech and Water Oak suffered no freeze loss.  The White Oak suffered minimal loss.

[RetiredTech]

  You are a little further north than I am. It may have been slightly colder there or lasted a little longer before it warmed up. I hope this winters weather isn't going to be the new norm. Warm temperatures confusing mother nature then a quick freeze. It's tough on everything. Had it lasted more than a few hours think of the damage it could have caused.

[SwampDonkey]

Not really any other way to explain it, than frost damage. Killed leaves and killed cambial cells in some with tender shoots. In severe cases a tree might even live 10 years but decline in health. In most cases trees recover. It may affect young trees harder than older ones. Warming temperature is key, but in most native trees, there is a threshold temperature that must be sustained or above that before dormancy breaks. Most native trees to that area will not burst open in 2 or 3 days of freakish heat. They have evolved to account for those events. Even moving plants from 30 miles away, northward, can effect them. This is proven out with various forestry provenance trials. Nurseries selling shrubs is another matter, we get outfits up here selling magnolia trees and certain rhododendrons that will mostly fail the cold test. Black walnut from southern Canada has been tried up here, it fails.