Here in sonoma county, northern california, home to Luther Burbank, I have had fabulous luck growing nopales by vegatatively propating pads I bought from the hispanic grocery store. I have 7-8 plants on the top and flanks of my hugelkultur bed and they are very happy. I planted about 12, some did not make it, but the ones that did have really taken off.
I think the ones from the store are selected and grown for their qualities as nopales...few spines, tender. So far I have not gotten any fruit but I harvest the paddles often (I LOVE them!). It is amazing how fast to see the pads grow from small buds to harvestable pads, given a little water. I noticed my pads were doing nothing, until I broke down and watered them with the soaker hose. But I only did so twice all summer long....and we get no rain at all from May to almost November. I also noticed that when the pads first bud out, they are covered in spines, but they seem to lose most their spines as they mature. What spines they do have are easy to peel, I never need to wear leather gloves.
My favorite way to cook them: seared trimmed of spines and whole in a hot, dry cast iron pan with another smaller cast iron pan nested on top as a weight (or similar pan)...I usually do 3-4 minutes per side. Sprinkle with soem garlic salt. Eat as is or add to salads, ratatouille, pair with roasted peppers, as a layer in a dagwood sandwich, added to ground beef for stuffed peppers, tacos filling, etc.
Also, brushed with olive oil and grilled...yum!
I substitute diced nopales for okra in jambalaya...very good. I also blanch diced nopales, then drain and add to diced jicama, jalepeno, cilantro, pinto beans, in a cumin lime vinegrette as a side dish.