Outside absolutely where you are, unless it ever does go below 25 F. or so.

I have the cork bark and the seju? varieties. they are 6" tall seedlings and ive been wondering if its possible to just plant them strait in the ground in zone 6 for several years and let them just grow as much as they want. If they cant make it this winter (I would need to keep in in cold garage instead), would they be any tougher by next winter, or would they still die no matter how big they are?
thanks castorcrap

Chinese elm are more than capable of taking much colder temps than the 25°F lots of people cite. They're quite hardy. The reason they're cited as indoor trees is because they're such strong growers that they will tolerate living indoors. Eventually the tree will begin to decline from continual growth and there may not be anything you can do for it. Letting the tree grow outside (thereby going dormant) will yield a much healthier and happier tree.

WF

Hi, All of my elms seem to prefer the outdoors, likewise to the info I've collected over the years from books & friends;but from what you@ve said your bonsai seems to enjoy it's indoor surroundings,so my advice would be "just keep it were it is!"
your's truly myagi

I often read posts about Ulmus p. that seem to conflict. The reason why appears easy to understand for me, but perhaps I'm wrong. I've never seen this presented as fact anywhere else, but from what I know of trees and provenance, it seems it must follow that it's true.

People, and trees from seed are unique. Trees that are vegetatively reproduced (cuttings, layers, etc) are not. They are clones or exact duplicates of the material from which the cuttings were taken.

Ulmus p. is somewhat unique, in that it is found growing in subtropical to temperate latitudes. Ficus carica is another tree, often discussed on GW that also occupies a wide range of latitudes. This is a very important consideration in deciding what is the exactly appropriate treatment for the tree. Provenance (where the genetic material originated) determines how the tree responds to changing day length and temperatures. A tree whose genetic material originated in southern FL will fare poorly if grown in NY. The tree will have great difficulty coping with the signals it receives about changing day length, and since cold-hardiness is not species determined (it is determined genetically within species) its probable that it will not have sufficient cold-hardiness to survive an outdoor NY experience, even with the pot buried in ground.

On the flip side. We have U. p. growing above the 45th parallel here in MI. If you take one of these hardy specimens and move it to southern FL, it will exhibit the same confusion over day length and will likely need a period of dormant rest to grow with good vigor in the next growth cycle, something it won't get in south FL.

So, I submit that in order to know what is appropriate treatment for U. p., we would need to know something about the provenance of the parent material from which the tree was produced; otherwise, it's just a guessing game.

Studies have shown that even moves of 100 miles in latitude are enough in some species to cause sufficient decline and weakening in the tree that it cannot resist insects or other pathogens. From this, I suppose it's not a big leap to expect that changes in provenance of a thousand or more miles would be sufficient to make a substantial difference in what is appropriate treatment for individual members of the same species and how those individual trees would respond to the cultural stimuli of day length and chill.

Al

thanks Al. makes sence. my tree is from florida. and I live in texas. so hopefully it will be able to handle everything o.k. I have gotten a lot of new growth from the tree since bringing it home. so far so good.