Fertilizer or ? to help tree withstand borderline zone temps?
I've likely asked this in the past...
I've killed pnumerous small ( 3') Sequoiadendron giganteum trees over the years. Most seemingly to winter damage. Supposedly there are some locally surviving each year here so it IS possible.
The next town over is significantly colder in winter (higher elevation), my guess being 5 degrees Celsius colder- and there are some beautiful specimens there. 50'+
So I've just planted a bigger one, with actual bark thinking maybe that could offer initial protection as well.
But, how about a good dose of potassium ASAP? May t hat help?
Anything else I could try?