Osage Orange - recovery mode

My Osage orange (Maclura pomifera) had a bad winter and spring. It got its first leaf in mid June -- weeks after everything else had a full head of green. There was a lot of twig dieback, too. It is supposed to be hardy to zone 4 (that's -20 to -30 degrees F); we had many nights in the teens (one into single digits) and several stretches where it never got above freezing for several days. The tree was buried in snow on my bench for about 2 weeks. This was its 4th winter here after its move from North Florida. It had leafed out in April in the first three years. It is native to N. Texas, and eastern Oklahome and SW Arkansas, but has been planted well up into Kansas and Missouri where it gets REAL cold.

(One other tree first leafed out about 3 days before this one -- a crape myrtle. It went through the same conditions.)

Anyway, when the Osage orange failed to leaf in April as usual, I repotted into a larger pot. I found a few mushy roots, which I removed. Then I just let it sit in the sun. When leaves finally reappeared, I cut away all the dead branches, including some long, lower branches which were entirely gone.

Here it is today -- front and back -- in its new pot and with a rounder shape.

The last pic is how it looked exactly one year ago.

I think I'm about the only one who has used this tree (unless some of you started after I posted my first pics about 10 years ago), but if anyone has a suggestion about how to prevent this in the future I'll happily listen.

Hi Jim,
I am glad that you managed to safe this small tree. And I say small TREE as a compliment! Very convincing peaceful image, well don!!
Keep it healthy!!!
Hans van Meer.

Thanks, Hans. The small tree stands 21 inches tall. It is one of my largest trees, though I know by most bonsaiests' standards these days it is a smallish tree. Most of my trees are in the 4-13 inch range.

Jim, trees in pots don't seem to share the same hardiness zones as others.
It seems healthy now though.