Sunday, November 18, 2007

winter protection

Lots of folks ask em about winter pritection. They are deeply concerned about doing the right thing. Well this here is what I consider the right thing for species which are hardy. I place them under the benches or next to the house in the shade. That's it. But this only applies to species which can tolerate their roots to be frozen stiff.


Rune Kyrdalen said...

Hi Walter. Do you leave trees like fagus sylvatica, carpinus betulus, tilia cordata and quercus robur outside so they are completly frozen during winter? What about Acer palmatum?

You said that you get down to minus 7 degrees in your greenhouse, so I guess that means that even trees like chinese quince and Acer buergerianum can take this much cold?


Walter Pall said...


some species are quite hardy in our climate as long as they are in the ground, but they are not hardy in a pot. They cannot stand total freezing of the rootball. These are all trees of the Quercus/Fagus section. They need special protection. The minimum is to store them on the ground and never leave them on shelves. Carpinus are hardy in winter but they have severe problems in late winter when they have already started to bud and late frosts occur. They need good protection then. Some species are quite hardy and will not die in winter anyway: Apple trees, most Prunus, Tilia. Ulmus are fine with cold too in general. The problem is that the branches are so brittle when frozen and brake. So they need good protecition from snow. I have left out trident maples, Japaenese maples, Chinese elms all winter long and the temperatures went dowon to minus 15 and more - and the trees happily survived.
I have to do such seemingly crazy things because I have more than 500 trees and no big storage room- nobody could pay for this. I just have to take chances. And I found that they stand much more than one would think.
If one has enough storage room it is always better to protect trees as far as possible. But don't over-protect them. They need a cold phase for at least six weeks.


Bogdan C. said...

We really appreciate your advices, Mr.Pall! A big thank you for everything!


Rune Kyrdalen said...

Thanks for the reply Walter!


Aaron said...

I also want to say thanks... this advice is extremely valuable to those of us who experience real winters.

JF (quatrefi) said...

Hello, Walter how are you?

Nice pictures !

Could you tell us wich species you protect in your storage-room?

Laegostromia, Myrtle, olive trees, (all mediterranean trees)?
What else?
Recebtly repoted trees, of courese (do you repot before winter, protecting the trees after?)

JF from Paris

Walter Pall said...


all mediteranean trees only. I do not repot after mid-September. I only repot conifers in fall. They don't need much protection, I hope for snow.


JF (quatrefi) said...

Thanks Walter...

Here's a link to my blog, where you can see almost 500 photos from Japan...
What a trip !

Sorry the comments are in french only...