Most of the long range weather predictions I have read point to a drier and warmer winter season than normal.  The effect of La Nina combined possibly with the warmer North Atlantic and Pacific waters could make for as little as 67% of normal winter precipitation.  Of course weathermen are notorious for getting it wrong, but still we can be prepared if they happen to be correct.   The 3 items of concern to our new trees are:

  1. Water and or drying
  2. Trunk protection
  3. Root protection

 

Water – Normally an apple tree in Central New Mexico doesn’t require any additional water between leaf drop and budding (approximately November through March). There generally is enough rain and snow to keep them in good shape. This however applies to an established and older tree, not one that has been recently planted. One thing to remember is that even when a tree looks dormant above ground the roots can still be growing below ground.  If the soil temperature is 45 degrees F or higher at the root depth (usually 12-18”) then the tree’s roots are still growing.  This is especially true with mulched trees which will help insulate the ground from cold and temperature extremes.  Also roots will only grow and form in damp soil, they will not seek out water as is often thought.  Strong root growth is what we are after to have maximum quality tree growth next year.  We will need to supplement water this winter if your tree does not get enough rain/snow and it doesn’t slowly soak into the soil.  How much is up to your specific site and microclimate.  If your tree is located in a dry and windy area without any mulch or cover you will need to monitor it closer than if it is well mulched and in a shady area. In general once a month should prove to be more than sufficient.  We want to supply about 10 gallons of water to the root zone per 1 inch of trunk diameter at a watering.

 Mulch – The best thing you can do is give your trees a 6-10” layer of organic mulch to at least a 3’ diameter around the young tree.  The first 12-18” diameter will be the active root zone. This layer of mulch will buffer the extreme swings in winter temperatures we have and also preserve the moisture in the soil.  Without moisture in the soil bacterial and other biological activity will be halted.  Also by mulching heavily we can extend the root growing season until later in the year. At the same time we are developing a more healthy, biologically active soil through organic material decomposition in the future root zone area.

 Trunk Protection – Our high altitude with less filtering of the suns rays through the atmosphere, the lower winter sun to the south, and our abundance of sunny winter days can cause heating on the trunks of trees, causing some cells to become somewhat active (de-acclimated to cold).  At night when the temperature can drop well below freezing the heated trunk cells will freeze and burst. This damage of the bark on the south and southwest side of tree trunks is called sunscald, frost cracks, or southwest disease. Young thin barked trees should have the trunks shaded on the south and southwest side or they can be wrapped using the tree trunk wrap found in garden centers. The trunks should be shaded or wrapped from November through early April. Alternatively the trunks can be painted with a mixture of 50% white latex paint and water though this is not an approved organic approach. Make sure to never use oil based or spray paints only diluted latex paints if you choose this method.  The white color reflects the suns rays and keeps the trunk cooler helping to prevent the sunscald.

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