This year’s once in 40 or 50 years freeze was a good time to test the varieties we have chosen and I am glad to see they held up very well to what Mother Nature could throw at them.  If they made it through this winter they will make it in any other winter.   But I have had many questions based around  “Why is it that some trees get damaged and others of the same kind don’t at the same temperature?”  So here is my short list ( top ten list):

1. Variety type – The plant was originally developed to be a hardy variety maybe to be grown up north or from another country so is genetically predisposed to endure more.

2. Location – If they are the same variety but grown in different climates, generally the ones grown in a warmer locale will not handle the cold as well as the same variety in a  colder climate.  It just hasn’t “hardened” the same.

3. Wet Soil – will move cold fast whereas dry soil will hold more air and insulates the roots better, especially if it is a quick short freeze.

4. Organic soil content – see #4 above, more organics= more air in “looser” soil.

5.  Mulch –  versus none of course helps to insulate.

6. Wind – The same temperature with wind will affect trees greatly.

7. MicroClimate – large rocks or block walls will hold and release some heat helping protect plant.

8. Length of Time – While it got to a certain temperature, how long was it there?

9. Time of year – In the middle of winter when trees are fully dormant they can handle much more cold than in late fall or early spring, especially if there is some sap movement in these times.

10. General health – how the tree has been cared for, proper level of fertilization,  amount of water and growth in summer, hardening off for dormancy etc.