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the_yard_guy

Tree winter dormancy

the_yard_guy
9 years ago

Hello All. We have had a rollercoaster of weather so far this fall/winter. November temps well below normal with snow, December temps in the 40s and 50s with no snow.

Question: most trees planted in ground and in containers in this area probably went into dormancy in mid November . With the fairly warm December weather would the trees possibly come out of dormancy and then go dormant again as temps drop or would trees simply stay dormant during these warm periods?

Thanks.

TYG

Comments (7)

  • ken_adrian Adrian MI cold Z5
    9 years ago

    define what you mead by dormancy ...

    even though they lose their leaves ... i am not sure.. it was cold enough.. long enough ... for the roots to go dormant ... [and have no clue in regard to your zone on that] ...

    in my z5 MI ... i am pretty sure.. when the ground freezes solid.. the roots ... above the frost free depth... are FULLY DORMANT ...

    so we have to begin with defining that.. before we can get to your premise ...

    and i think it will have to be an either/or premise of mother earth vs pots ... heck.. potted material can come out of dormancy if you sneeze on it ...

    and the secondary issue ... premised on the first ... what do you mean by coming out of dormancy .... if you mean root growth.. there would be one answer ... if you mean.. leaf out.... then there is another answer ...

    perhaps you can guide us.. to where you want to go with the issue???

    let us know where you are.. as z6 ... doesnt tell us much ....

    ken

  • fruitnut Z7 4500ft SW TX
    9 years ago

    Yard guy:

    For most fruit trees adapted to zone 6 a warm spell in Dec causes a reduction in cold hardiness of several degrees F. The trees will reach maximum hardiness in mid winter if temperatures stay continuously below freezing. Each day it stays below freezing all day increases hardiness about 1F per day until max hardiness is reached. Each day above freezing decreases hardiness 1F.

    Dormancy is complicated and cold hardiness is only one aspect but a very important factor.

    Low chill trees could begin to procede towards growth during a mid winter warm spell. High chill trees generally won't lose dormancy in Dec. They won't be fully chilled that early.

  • the_yard_guy
    Original Author
    9 years ago

    Ken: Thanks for the reply. Guess I should add more details. West Michigan here, not too far from you, maybe 1 hour west.

    I'm growing small seedlings, maple, spruce, and fir, both in ground and in containers. I recall you saying that once a tree goes dormant for the winter it's important that the tree remains that way until Spring. I have read that tree and root damage or even death can happen if a dormant tree in a cold or frozen container is brought inside a warm house for a few days or weeks, thaws out and begins to come out of dormancy, then is placed back outdoors in very cold temperatures.

    So with the very cold November temperatures, and then very mild December temperatures, I'm wondering what happens when a tree, an Abies fraseri for example, in a container goes dormant when it gets cold, and then the weather warms up and the container soil thaws out. Does the tree begin to wake up and come out of dormancy, or does it remain dormant? This would be root dormancy, not leaf buds opening.

    Does that make sense?

  • Huggorm
    9 years ago

    Some trees, like oaks, does measure day length and wont get out of dormancy before a certain amount of hours of light is reached. Other trees does not seem to care about that at all.

  • androidbabbles
    9 years ago

    Tree winter Dormancy is a period in an organism's life cycle when growth, development, and (in animals) physical activity are temporarily stopped. This minimizes metabolic activity and therefore helps an organism to conserve energy.
    Thank you!

  • plumstupid
    9 years ago

    If oak trees depend on day length to break dormancy then why were they hit so hard during the Easter freeze of 2007? They were growing like crazy that year by mid March. Maybe it's a combination of factors of chill hours,day length, temperature and who knows what else. I'm a fruit tree peep so take it easy on me.

  • poaky1
    9 years ago

    I would guess that by April those oaks have had enough of a dormancy period, but will likely not have in Dec -Feb, if they grow as far south as Ga, where in southern ga they may be growing in March in zone 8. If that makes sense. I'm guessing, someone will 'splain the real answer. Poaky1