Canadian peat should be ok. It seems as if misty might be one of those nearly wild ones. Or in need of a pruning. I'm not sure, but I bet they're TOPS for dehydrating, baking, fresh eating. Up north we have little giant. Do some searches here on the site for lots of good postings/threads.
good luck

You'd be better off with spaghnum peat moss. This is the kind that is brown and fiberous. It's also acidic. Canadian peat moss is usually the black kind and not as acidic. Plus the black peat doesn't drain as well. The first requirement of any potting mix is good drainage.

To make them grow dissolve 1 Tablespoon 21-0-0, ammonium sulfate, in 2-3 gal water and use that to water once a week. In between use straight water. This will push rapid growth in about 4-6 weeks.

Small fruit could be from lack of water or too much fruit. Often some fruit needs to be removed by pruning or hand thinning. Misty often over bears so not sure why the short crop. Perhaps it was the lack of growth.

Thanks for the replies. Where does one get 21-0-0 ammonium sulfate? Is that just Nitrogen being added?

Try tractor supply, Rural King, type of store.I pay $13 for 50 lbs.
It's cheap. Looks like salt with a yellow tinge to it.