Although you can overwinter chard, for final picking, they will soon bolt.
If its Perpetual spinach, mine normally last for a few years.
Did many many moons ago, move some Perpetual spinach in Spring after the plant had overwintered (moved to a new raised bed) and it worked fine.
As above, they plants will have a bulky root base.
I dug in a trowel around the root that I felt first and pulled up the root and soil with it and it transplanted with ease and produced a good crop for another year.
One thing I do love abut Perpetual spinach, is its available for harvest through the year with continuing two year and new plants.
Easier though is to get some sown. My perpetual Spinach was sown second week of March and the seedlings are now a few inches high. Will be transplanting outside in a few weeks.
Will be sowing my Chard probably next week or so and plant out late April.
By the way my perpetual Spinach freezes fine.
I freeze some every time I pick too much. Mainly to drop in a lasagne. Cooks out from frozen in minutes or just steamed for 15 minutes from frozen.
I wash it, squeeze the water out well ' an old fashioned salad spinner', make into 'tennis size' balls and place the balls into a container in the freezer straight away. No blanching.
Nice thing is the balls do not stick together at all really, so you can just keeping adding and pull out one easily.
Never tried freezing Chard, not sure it would quite have or hold onto the same consistency.
